GIFT  OF 


Zooli  dept. 


BIOLOGY 


PRACTICAL  ZOOLOGY 


AN   ELEMENTARY  TEXT-BOOK   TREATING   OF 

THE   STRUCTURE,   LIFE   HISTORY,   AND 

RELATIONS   OF  ANIMALS 


BY 


ALVIN    pAVISON,  A.M.,  PH.D. 

Professor  of  Biology  in  Lafayette  College;  Fellow  of  the  American 

Association  for   the   Advancement   of  Science; 

Author  of  Mammalian  Anatomy,  etc. 


NEW  YORK  .-.  CINCINNATI  .-.  CHICAGO 
AMERICAN  BOOK   COMPANY 


LIBRAW 

G 


COPYBIGHT,  1906, 
BY 

ALV1N  DAVISON 

Davison's  Zoology 
w.  P.    7 


PREFACE 


IN  most  cases  where  only  one  of  the  two  biological 
branches  is  included  in  the  curriculum  of  a  secondary 
school,  botany  is  chosen.  This  is  probably  due  not  only 
to  the  fact  that  few  teachers  have  studied  zoology,  but 
also  to  the  difficulties  incident  to  the  teaching  of  the  sub- 
ject and  the  impractical  kind  of  zoology  to  which  too  many 
teachers  have  been  introduced.  In  many  schools  the 
college  graduate  has  inflicted  on  his  pupils  in  their  lower 
teens  the  zoology  adapted  to  college  students.  Laborious 
dissections,  permitting  the  details  of  structure  to  be  noted 
and  wearisome  drawings  to  be  made,  may  be  of  value  to 
the  few,  but  render  injustice  to  many. 

The  plan  of  teaching  the  biological  sciences  lately  in 
many  schools  has  sacrificed  the  acquisition  of  important 
information  and  the  training  of  the  powers  of  reflection 
and  expression  to  the  cultivation  of  the  powers  of  observa- 
tion and  the  teaching  of  drawing.  The  average  individual 
cares  little  about  the  names  of  the  parts  of  the  crayfish's 
legs  or  the  veins  in  the  wings  of  insects,  but  he  must  be 
stupid  indeed  who  is  not  interested  hi  the  interdependence 
of  species,  the  part  played  by  insects  in  the  transmission  of 
disease,  the  marvelous  life  history  of  the  creatures  with 
which  he  comes  into  daily  contact,  and  the  meaning  of  the 
animal  architecture  so  common  in  the  crowded  city  as  well 
as  by  the  unfrequented  wayside.  It  is  far  more  important 

5 

255377 


PREFACE 


that  the  pupils  should  become  acquainted  with  some  of  the 
important  works  on  zoology  and  thus  learn  where  infor- 
mation may  be  secured  on  the  topics  in  which  they  may 
be  interested,  than  to  spend  much  time  in  memorizing 
terms  and  recording  details  never  to  be  of  any  service  in 
later  life.  The  most  effective  mental  discipline  is  experi- 
enced by  him  who  investigates  any  assigned  subject  by 
personal  observations  of  the  animals  concerned,  and  by 
consulting  the  several  pamphlets  and  books  treating  of  the 
subject,  and  then  after  arranging  his  information  in  logical 
order  presents  it  to  the  rest  of  the  class  in  language  and 
drawings  sufficiently  clear  to  be  comprehended. 

The  growing  custom  of  allowing  the  work  recorded  in 
the  note  book  to  take  the  place  of  oral  recitation  is  a  bad 
one.  The  mental  discipline  and  exhilaration  resulting 
from  the  expression  of  one's  matured  thoughts  before 
his  associates  can  be  secured  in  no  other  way.  A  number 
of  questions  should  be  assigned  the  class  for  each  recita- 
tion, in  addition  to  one  or  two  special  topics  to  be  reported 
on  by  one  or  two  members  allowed  a  week  or  more  to  in- 
vestigate them.  In  some  schools  the  instructor  will  find 
it  wise  to  omit  certain  subjects  discussed  in  the  text  owing 
to  the  need  of  time  for  more  extended  laboratory  work  and 
the  investigation  of  topics  in  which  his  community  may 
be  specially  interested. 

A  comparatively  small  amount  of  laboratory  work  is 
indicated,  and  the  animals  to  be  used  are  such  as  may  be 
secured  almost  anywhere.  Detailed  directions  concern- 
ing the  examination  and  dissection  of  specimens  have  been 
largely  omitted  in  order  that  the  pupil  may  have  some  op- 
portunity to  think  for  himself.  Moreover,  different  schools 


PREFACE  7 

are  unable  to  carry  on  the  laboratory  work  on  the  same 
animals  with  the  same  degree  of  thoroughness.  Those 
who  are  unable  to  secure  any  material  for  study  will  find 
in  the  illustrations  excellent  substitutes,  but  it  is  hoped 
that  every  teacher  will  strive  to  afford  his  pupils  that 
mental  stimulus  and  specially  valuable  mind  culture  re- 
sulting from  a  face  to  face  acquaintance  with  animal  life. 
At  best,  it  is  impossible  to  secure  all  the  material  necessary 
to  demonstrate  the  ideas  to  be  taught,  and  therefore 
numerous  illustrations  have  been  introduced.  Much  time 
and  expense  have  been  given  to  the  preparation  of  the 
photographs,  which  can  be  relied  on  as  representing  facts 
more  accurately  than  drawings,  and  approaching  as  nearly 
as  possible  to  nature  itself. 

The  subject  matter  has  been  so  treated  as  to  adapt  the 
book  to  schools  giving  either  a  half  or  whole  year  to  the 
study  of  zoology.  Those  preferring  it  can  begin  the  study 
with  the  Protozoa  and  proceed  to  the  higher  forms,  instead 
of  following  the  order  given  in  the  text,  as  the  chapters  in 
Parts  I  and  II  are  so  written  as  to  be  largely  independent 
of  each  other.  Teachers  having  only  a  half  year  for 
Zoology  will  perhaps  find  it  wise  to  omit  certain  chapters 
in  order  that  the  time  which  ought  to  be  spent  in  studying 
the  animals  shall  not  be  devoted  to  the  study  of  the 
book.  It  is  not  expected  that  most  schools  will  be  able 
to  give  careful  attention  to  all  the  subjects  treated,  but 
the  numerous  forms  and  phases  of  animal  life  have  been 
presented  in  order  to  allow  some  choice  on  the  part  of 
the  teacher  desiring  to  emphasize  special  features  of 
zoological  study. 

Mr.  D,  S,  Hartline,  of  the  State  Normal  School  at  Blooms- 


8  PREFACE 

burg,  has  rendered  me  efficient  assistance  in  reading  and 
criticising  the  entire  manuscript,  while  numerous  other 
students  of  nature  to  whom  credit  is  given  in  the  text  have 
contributed  drawings,  photographs,  and  suggestions,  add- 
ing much  to  the  value  of  the  book. 

ALVIN  DAVISON. 

LAFAYETTE  COLLEGE,  EASTON,  PA. 


CONTENTS 


INTRODUCTION 

PAGE 

METHODS,  EQUIPMENT,  ETC 11 

CLASSIFICATION   .  25 


PART  I 
The  Arthropoda  :  Segmented  Forms  with  Jointed  Legs 

1.  ORTHOPTERA 30 

2.  DlPTERA 39 

3.  HYMENOPTERA 52 

4.  LEPIDOPTERA 68 

5.  HEMIPTERA 91 

6.  COLEOPTERA       . 107 

7.  NEUROPTERA,  EPHEMERIDA,  AND  ODONATA    ......  116 

8.  ARACHNIDA  AND  MYRIAPODA 125 

9.  CRUSTACEA 133 

PART  II 
The  Anarthropoda:  Invertebrates  without  Jointed  Legs 

10.  MOLLUSCA 142 

11.  VERMES 150 

12.  ECHINODERMATA 161 

13.  CCELENTERATA  AND  PoRIFERA 167 

14.  PROTOZOA  :  ONE-CELLED  MICROSCOPIC  ANIMALS  ....  178 

9 


10  CONTENTS 

PART  III 
Vertebrate 

PAGE 

15.  PISCES 185 

16.  AMPHIBIA 199 

17.  REPTILIA 211 

18.  AVES 226 

19.  MAMMALIA 261 

PART  IV 
Animal  Life 

20.  FROM  EGG  TO  ADULT 293 

21.  SENSES  OF  ANIMALS 303 

22.  PROTECTION  FROM  ENEMIES 310 

23.  PARASITISM      323 

24.  VANISHING  SPECIES       334 

25.  ORIGIN  OF  THE  DIVERSE  FORMS  OF  ANIMA.L  LIFE  .   .    ,  342 


INTRODUCTION 


METHODS,    EQUIPMENT,    ETC. 

The  Biological  Sciences.  —  All  living  things  belong  either 
to  the  plant  or  to  the  animal  kingdom.  An  individual  of 
either  group  is  termed  an  organism.  A  study  of  the  ani- 
mal organisms  constitutes  the  science  of  zoology,  while 
botany  has  for  its  field  the  investigation  of  plant  life.  The 
science  of  biology  includes  both  botany  and  zoology. 

Any  animal  or  plant  may  be  considered  from  several 
different  standpoints.  A  general  study  of  structure  and  of 
the  relations  of  the  various  systems  and  organs  is  known  as 
anatomy.  The  location  and  parts  of  the  heart  and  courses 
of  the  nerves  and  blood  vessels  are  questions  belonging  to 
this  science.  Physiology  has  for  its  province  the  investiga- 
tion of  the  functions  of  the  organs  and  systems,  and  there- 
fore explains  the  uses  of  the  heart,  lungs,  and  blood  vessels. 
Inquiries  relating  to  the  home  life,  food,  enemies,  and  ex- 
ternal appearance  of  animals  belong  to  the  domain  of 
Natural  History,  which  also  concerns  itself  with  the  same 
phases  of  plant  life. 

Value  of  Zoological  Study.  —  It  is  proper  that  both 
teacher  and  pupil  should  keep  in  mind  the  advantages  to  be 
derived  from  the  study  of  animal  life,  that  time  may  not  be 
wasted  on  insignificant  details.  In  fact  it  is  the  duty  of 
every  teacher  to  present  only  such  portions  of  a  science  as 
11 


12  INTRODUCTION 

will  be  of  the  greatest  economic,  educational,  and  ethical 
value  to  the  learners. 

Economic  Zoology  has  lately  proved  itself  worthy  of  the 
consideration  of  every  American  citizen.  The  number  of 
injurious  insects  in  the  United  States  is  large  and  increas- 
ing. They  often  destroy  one  fourth  or  even  a  half,  and 
sometimes  the  entire  crop  of  a  whole  section.  The  agri- 
cultural products  of  our  country  amount  annually  to  about 
$3,000,000,000,  while  the  loss  of  crops  from  the  attacks  of 
insects  is  estimated  at  $100,000,000.  In  1874  in  the 
Western  states,  the  Rocky  Mountain  locust  caused  over 
$40,000,000  of  damage.  The  chinch  bug  (Fig.  116)  in 
Illinois,  during  the  year  1864,  destroyed  $70,000,000  worth 
of  crops,  and  in  Missouri  ten  years  later  was  responsi- 
ble for  the  loss  of  nearly  $20,000,000  worth  of  produce. 
The  governor  of  Texas  recently  made  an  offer  of  $50,000 
to  any  one  who  should  discover  a  remedy  for  the  ravages 
of  the  cotton-boll  weevil  (Fig.  121) .  The  San  Jose  scale 
(Fig.  107)  destroys  acres  of  valuable  fruit  orchards  an- 
nually. A  much  greater  loss  to  crops  would  result  yearly 
were  it  not  for  the  fact  that  men  have  learned  by  the  study 
of  zoology  how  to  control  some  of  the  insect  pests,  and  also 
how  to  secure  the  greatest  benefits  from  birds  and  a  large 
class  of  insects  naturally  helpful  to  man.  Ignorance  con- 
cerning the  food  of  hawks  and  owls  caused  the  Pennsyl- 
vania legislators  in  1885  to  pass -a  law  resulting  in  a  loss 
to  the  state  of  $2,000,000.  By  becoming  acquainted  with 
the  habits  of  animals,  man  is  able  to  have  dominion  over 
them,  and  by  wise  legislation  to  make  such  laws  in  regard 
to  their  destruction  or  preservation  as  will  be  to  the  best 
interests  of  not  only  the  present  but  future  generations. 


METHODS  13 

The  Educational  Value  of  zoological  studies  can  not 
be  overestimated.  They  furnish  the  means  of  bringing 
nature  and  the  child  into  direct  contact,  so  that  he  may 
actually  acquire  some  knowledge  by  his  own  powers  of 
perception.  Froebel  says,  "  We  do  not  feel  the  meaning 
of  what  we  say,  for  our  speech  is  made  up  of  memorized 
ideas  based  neither  on  perception  nor  on  productive  effort." 

Animal  life  properly  studied  develops  not  only  the  facul- 
ties of  acquisition,  but  likewise  the  powers  of  reflection  or 
reasoning  and  expression.  Essay  writing  and  memoriter 
recitations  are  too  often  wearisome,  but  if  the  pupil  has 
learned  something  of  vital  interest  concerning  an  animal's 
life  history,  habits,  and  struggle  for  existence,  he  will  find 
pleasure  in  relating  his  discoveries  to  his  classmates,  and 
thereby  will  experience  a  splendid  training  in  the  use  of 
intelligent  English. 

The  Ethical  Value  to  be  derived  from  the  study  of 
zoology  depends  largely  on  how  the  subject  is  taught. 
Much  evil  is  wrought  in  our  land  through  ignorance. 
Youth  seldom  stop  to  think  how  much  harm  is  done  when 
they  ruthlessly  destroy  life.  The  maiming  of  a  single 
bird  may  mean  death  to  many  little  ones.  A  careful  esti- 
mate shows  that  only  about  half  as  many  birds  exist  to-day 
as  were  present  in  our  country  a  quarter  of  a  century  ago. 
One  chief  factor  causing  the  decrease  has  been  ignorance 
on  the  part  of  the  people  who  have  sanctioned  the  robbing 
of  nests  and  killing  of  birds.  Every  boy  and  girl  should 
go  forth  from  school  imbued  with  the  idea  that  the  killing 
of  our  best  friends  in  the  animal  world  merely  to  satisfy  a 
savage  instinct  is  a  crime.  A  face  to  face  acquaintance 
with  the  creatures  of  earth  should  gain  many  warm  ad- 


14  INTRODUCTION 

vocates  of  the  Society  for  the  Prevention  of  Cruelty  to 
Animals.  Moreover,  to  him  who  understands  the  meaning 
of  the  well-woven  nest  by  the  roadside,  the  glistening  eggs 
on  the  tender  twig,  and  the  thousand  other  sights  and 
sounds  of  the  lane  and  park,  there  is  no  nook  or  cranny  of 
creation  without  a  wholesome  interest. 


EQUIPMENT 

Plan  of  Work.  —  It  is  not  important  that  the  pupils 
should  learn  many  things,  but  it  is  important  that  they 
should  be  taught  to  observe  accurately,  to  reason  carefully, 
and  to  express  their  thoughts  in  clear  English.  The 
teacher  will  be  asked  many  questions  about  animals,  which 
he  can  not  answer,  and  therefore  he  must  realize  there  is  no 
disgrace  in  saying;  "  I  do  not  know,  but  let  us  together  seek 
the  information  in  the  books  and  in  the  animals  them- 
selves." Pupils  should  be  encouraged  to  ask  questions, 
and  those  which  can  not  be  easily  answered  may  be  assigned 
to  one  or  more  individuals  for  study  during  the  next  several 
days.  Agassiz's  motto,  "  Study  nature,  not  books/'  ought 
to  hang  in  every  schoolroom.  This  text-book  is  not  to 
be  memorized;  it  aims  merely  to  furnish  to  inquiring  minds 
information  about  animals. 

If  the  class  becomes  specially  interested  in  scale  insects 
and  plant  lice,  or  birds  and  insects,  or  mosquitoes  and 
other  flies,  it  is  wise  to  devote  much  time  to  these  and 
give  less  study  to  other  forms.  Many  teachers  will  find  it 
wise  to  omit  certain  chapters  and  some  parts  of  other 
chapters,  to  save  time. 


EQUIPMENT  15 

Each  instructor  should  choose  those  subjects  for  which 
he  can  most  easily  secure  the  material,  and  if  possible 
study  the  various  forms  of  life  during  that  season  of  the 
year  when  they  are  most  active.  Insects  are  best  studied 
in  the  autumn,  the  birds  in  early  summer,  the  reptiles  and 
amphibians  in  early  spring,  and  the  lower  invertebrates 
and  mammals  hi  winter.  If  only  one  term  is  devoted  to 
zoology  fewer  reference  books  will  be  required  and  a  smaller 
number  of  animals  should  be  considered. 

As  in  most  cases  it  is  impossible  to  observe  out  of  doors 
all  the  stages  in  the  life  history  of  a  species,  pupils  must 
learn  to  study  carefully  the  illustrations  in  the  book  and 
also  make  use  of  well-preserved  specimens. 

Preservation  of  Material.  —  Nothing  else  will  create 
so  much  interest  in  this  branch  as  the  collection  and  pre- 
servation of  animals  to  be  used  not  only  by  the  present 
but  also  by  future  classes.  Nearly  all  insects  in  the  adult 
state  may  be  preserved  by  merely  allowing  them  to  dry  in 
the  air  five  or  six  days  after  the  legs  and  wings  have  been 
arranged  and  pinned  in  the  desired  positions. 

A  pine  board  to  which  are  tacked  two  or  three  sheets  of 
blotting  paper  makes  a  good  pinning  board.  If  the  wings 
are  to  be  sprsad  the  insect  should  be  laid  on  its  back,  other- 
wise it  may  be  placed  in  its  natural  position.  In  either 
case  pins  should  be  so  stuck  as  to  hold  all  parts  without 
penetrating  the  animal. 

Dried  material  will  be  destroyed  by  museum  pests  unless 
placed  in  tight  boxes,  which  can  be  made  by  any  boy  or 
girl.  Secure  two  panes  of  glass  of  equal  size.  If  they 
measure  eight  by  ten  niches,  saw  from  a  thin  board  four 
strips  a  half  inch  wide,  and  make  two  of  them  eight  inches 


16  INTRODUCTION 

long  and  the  other  two  nine  inches,  so  that  when  put  to- 
gether they  will  form  the  sides  of  the  box  whose  top  and 
bottom  are  the  panes  of  glass.  With  mucilage  or  royal 


FIG.  1.— Pinning  board.  Strips  of  paper  hold  the  wings,  a,  Cicada;  6,  butter- 
fly ;  c,  wood-boring  beetle ;  d,  dragon  fly ;  e,  pupa  of  hawk  moth ;  /,  galley 
worm. 

glue  cement  the  strips  to  one  pane  and  let  them  dry  over 
night,  keeping  them  pressed  closely  to  the  glass  by  the 
weight  of  a  heavy  book.  In  place  of  wood,  seven  or  eight 
strips  of  thick  pasteboard  glued  one  on  top  of  another 


EQUIPMENT 


17 


FIG.  2.  — First  step  in  making  an  insect  cabinet. 

may  serve  for  the  sides  of  the  box.    At  any  time  later,  the 
insects  may  by  a  drop  of  glue  be  stuck  to  the  pane  form- 


FiG.  3.  —  Cabinet  5  by  7  inches  completed.    Cost,  six  cents. 


ing  the  bottom  of  the  box  and  then  the  top  pane  glued  on. 
A.  neat  appearance  can  be  given  the  cabinet  by  edging  it 


18 


INTRODUCTION 


with  passe-partout  picture  binding,  to  be  had  at  any  book- 
store or  photographic  supply  house.  If  one  such  cabinet 
is  prepared  each  year,  a  valuable  natural  history  collection 
will  soon  result.  The  centipeds  and  spiders  may  be 
mounted  in  the  same  manner  as  insects,  but  other  animals 
are  better  preserved  in  alcohol  or  formalin. 

A  very  neat  method  of  mounting  small  insects  is  that 
of  gluing   the  specimens  to  a  piece  of  glass  and   placing 

over  them  a  watch  crys- 
tal held  in  place  by  a 
few  drops  of  glue. 

Pure  formalin  or  for- 
maldehyde may  be  pur- 
chased at  the  drug  store 
for  about  fifty  cents  per 
pint  bottle.  One  part 
of  this  mixed  with 
twenty  parts  of  water 
makes  a  solution  that 
will  preserve  any  plant 
or  animal.  In  case  the 
animal  is  large,  such  as 
a  snake  or  rat,  one  or 
two  long  slits  should  be 
made  in  the  abdominal 
wall  so  that  the  fluid 
may  reach  the  internal  organs.  Wide-mouthed  bottles 
and  fruit  jars  or  small  stone  jars  are  the  best  receptacles  for 
these  specimens. 

Painless  death  may  be  effected  in  a  half  hour  by  placing 
any  animal  in  a  tight  jar  or  box  with  a  bunch  of  cotton  or 


FIG.  4.  — Watch-crystal  mount. 


EQUIPMENT  19 

cloth  on  which  have  been  placed  thirty  or  forty  drops  of 
chloroform  for  every  hundred  cubic  inches  of  space.  A 
convenient  killing  jar  for  insects  is  made  by  having  a  drug- 
gist place  in  a  wide-mouthed  fruit  jar  five  cents'  worth  of 
potassium  cyanide  in  small  pieces,  which  must  be  covered 
with  a  thick  solution  of  plaster  of  Paris  in  water.  In 
order  that  the  plaster  may  dry  the  jar  should  be  left  open 
a  day  or  two  and  then  kept  closed  except  when  putting  in 
or  removing  animals.  Potassium  cyanide  is  a  deadly 
poison.  A  wide-mouthed  cyanide  bottle  is  convenient 
for  pupils  to  use  in  the  field. 

Keeping  Live  Animals. — With  but  slight  trouble  and 
great  profit  many  animals  may  be  kept  alive  in  the  school 
room  or  laboratory.  Snakes,  turtles,  and  lizards  live  com- 
fortably in  a  covered  box  containing  dry  earth  and  a  soup 
plate  with  water.  A  turtle  will  eat  fresh  beef,  but  the 
lizard  and  snake  need  a  weekly  meal  of  beetles,  flies,  or 
earthworms.  Tadpoles,  newts,  fish,  water  fleas,  various 
insect  larvae,  a  few  worms,  hydra,  and  many  protozoans 
flourish  in  aquaria  consisting  of  glass  jars  or  dishes  filled 
with  water  and  containing  a  few  water  plants.  The  water 
need  not  be  changed  if  the  bulk  of  the  plants  is  about  one 
fourth  that  of  the  animals.  A  few  bits  of  fresh  beef  should 
be  given  the  vertebrates  once  a  week.  The  aquarium 
needs  good  light  but  not  necessarily  direct  sunshine  in 
order  that  the  plants  may  flourish  and  furnish  oxygen  for 
the  animals.  Gallon  battery  jars  to  be  had  of  the  Whitall, 
Tatum  Co.,  of  New  York,  serve  excellent  aquarium  pur- 
poses and  cost  but  fifteen  cents  each. 

If  animals  which  one  can  not  secure  in  his  own  locality 
are  desired,  they  may  be  obtained  of  the  following  dealers: 


20 


INTRODUCTION 


American  Entomological  Company,  1040  DeKalb  Ave., 

Brooklyn,    N.   Y.     All   kinds   of  insects.     Catalogue 

on  application. 
Brimley  Bros.,  Raleigh,  N.  C.     Living  and  preserved 

animals. 
Biological  Laboratory,  Cold  Spring  Harbor,  L.  I.,  N.  Y. 

Marine  animals.     Catalogue  on  application. 
Tufts  College  Laboratory,  South  Harpswell,  Me. 
Hopkins  Seaside  Laboratory,  Stanford  University,  Cal. 


FlG.  5.  —  Dissecting  instruments. 

St.  Louis  Biological  Laboratory,  St.  Louis,  Mo.  Numer- 
ous kinds  of  animals  and  microscopical  slides  showing 
structure  of  animals.  Catalogue  on  application. 

The  Laboratory.  —  This  should  be  a  well-lighted  room 


EQUIPMENT  21 

containing  a  number  of  tables  with  drawers  for  the  use  of 
the  pupils,  and  several  shelves  or  cases  for  holding  pre- 
served material.  If  such  a  workroom  is  not  available 
two  or  three  tables  placed  in  the  schoolroom  will  be  found 
of  great  use.  For  those  who  wish  to  do  much  in  the  line 
of  dissection  a  few  thirty-five  cent  scalpels,  or  dissecting 
knives,  forceps,  needles,  scissors,  and  trays  both  of  tin 
and  wood  are  necessary.  The  bottoms  of  the  tin  trays 
should  be  covered  with  a  quarter-inch  layer  of  melted 
paraffine  to  which  the  small  animals  are  to  be  pinned  while 
being  dissected  under  water. 

At  least  one  or  two  compound  microscopes  are  neces- 
sary. A  satisfactory  instrument  can  be  purchased  for 
about  $30.  A  few  dissecting  microscopes  costing  about 
$2.50  each  are  of  service  in  the  study  of  many  forms. 

A  half  gross  of  glass  object  slides  and  a  half  ounce  of  num- 
ber two  cover  glasses  are  required  for  the  examination  of 
microscopic  objects.  A  bottle  of  chloroform  and  a  quarter 
of  an  ounce  of  chloretone  dissolved  in  a  quart  of  water 
should  be  ready  for  use  as  described  in  the  special  lessons. 

Books.  —  The  pupils  in  addition  to  their  text-books 
will  take  an  interest  in  consulting  the  following  references 
if  they  are  accessible: 

APGAR,  A.  C. :  Birds  of  the  United  States.  American  Book  Com- 
pany. $2.00.  Will  help  one  to  identify  the  birds  in  the  hand 
or  in  the  field. 

*BERGEN,  J.  Y.  and  F.  D:  A  primer  of  Darwinism  and  Organic 
Evolution.  Lee  &  Shepard.  Boston.  $1.25.  Explains  how 
species  have  originated. 

*BLANCHAN,  NELTJE:  Bird  Neighbors.  Doubleday,  Page  &  Com- 
pany. New  York.  $2.00.  Contains  colored  plates  and  enables 
one  to  identify  one  hundred  and  fifty  birds  in  the  field. 


22  INTRODUCTION 

BUBNET,  MARGARETTA:  Zoology  for  High  Schools  and  Academies 
American  Book  Company. 

*CHAPMAN,  F.  M.:  Bird-Life.  D.  Appleton  &  Company.  New 
York.  $1.75.  A  good  book  for  beginners. 

DAVENPORT,  C.  B.  and  G.  C:  Introduction  to  Zoology.  Mac- 
millan  &  Company.  New  York.  $1.10. 

DAVISON,  ALVIN:  Mammalian  Anatomy.  P.  Blakiston's  Son  & 
Company.  Philadelphia.  $1.50.  Treats  of  the  preparation 
and  preservation  of  mammals  for  dissection  and  their  anatomy. 
Valuable  for  a  teacher  of  physiology. 

DODGE,  C.  W.:  General  Zoology.  American  Book  Company. 
New  York. 

HORNADAY,  W.  T. :  American  Natural  History.  Charles  Scribner's 
Sons.  New  York.  $3.50.  Treats  of  vertebrates  only. 

*!NGERSOLL,  E. :  Nature's  Calendar.  Harper  and  Brothers.  New 
York.  $1.50.  Contains  practical  suggestions  for  outdoor  obser- 
vations. 

JORDAN,  D.  S. :  Manual  of  Vertebrate  Annuals  of  Northern  United 
States.  McClurg  &  Company.  Chicago.  $2.50.  Enables  one 
to  identify  any  vertebrate. 

KJNGSLEY,  J.  S.:  Elements  of  Comparative  Zoology.  Henry  Holt 
&  Company.  New  York.  $1.20. 

LECONTE,  J.:  Evolution  and  its  Relation  to  Religious  Thought. 
D.  Appleton  &  Company.  New  York.  $1.50. 

*LUCAS,  F.  A. :  Animals  of  the  Past.  McClure,  Phillips  &  Com- 
pany. New  York.  $2.00.  A  popular  account  of  fossil  remains. 

MARSHALL,  C.  M.  and  HURST,  C.  H-:  Practical  Zoology.  G.  P. 
Putnam.  New  York.  $3.50.  Directions  are  given  for  dissect- 
ing rabbit,  pigeon,  dogfish,  and  other  forms. 

*NEEDHAM,  J.  G. :  Outdoor  Studies.  American  Book  Company. 
New  York.  $  .40. 

PARKER,  T.  J.  and  HASWELL:  Text-book  of  Zoology.  Macmillan 
&  Company.  New  York.  $9.00.  A  thorough  and  clear  treat- 
ise. 

*SANDERSON,  E.  D. :  Insects  Injurious  to  Staple  Crops.  Wiley  & 
Company.  New  York.  $1.50. 


EQUIPMENT  23 

*STOKES,  A.  C. :  Aquatic  Microscopy  for  Beginners.     E.  F.  Bige- 

low.     Portland,     Connecticut.     $1.25.     Useful    in    identifying 

small  water  animals. 
*WEED,  C.  M.  and  DEARBORN,  N. :  Birds  in  their  Relation  to  Man. 

J.  P.  Lippincott  &  Company.      Philadelphia.      A  valuable  book. 

The  books  in  the  above  list  marked  with  an  asterisk  will  be  found 
most  valuable  for  elementary  work. 

Every  school  will  find  interesting  and  valuable  information  in 
the  Yearbooks  of  the  Department  of  Agriculture  which  may  be  had 
free  of  charge  by  applying  to  the  United  States  senator  or  repre- 
sentative of  the  district  in  which  the  school  is  located.  Back 
numbers  may  be  had  at  second-hand  book  stores  for  about  twenty 
cents  each. 

The  following  useful  bulletins  and  circulars  will  be  sent  free  upon 
application  to  the  Secretary  of  Agriculture,  Washington,  D.  C. 

Some  Insects  Injurious  to  Stored  Grain,  pp.  24,  figs.  18. 

Insects  Affecting  the  Cotton  Plant,  pp.  32,  figs.  18. 

Some  Common  Birds  in  Their  Relation  to  Agriculture,  pp.  48. 

Bee  Keeping,  pp.  32,  figs.  19. 

The  Principal  Insect  Enemies  of  the  Grape,  pp.  23,  figs.  12. 

The  Peach  Twig-Borer,  pp.  16,  figs.  5. 

Three  Insect  Enemies  of  Shade  Trees,  pp.  30,  figs.  11. 

The  Principal  Insects  Affecting  the  Tobacco  Plant,  pp.  32,  figs. 
25. 

Important  Insecticides,  pp.  42,  figs.  6. 

The  Principal  Insect  Enemies  of  Growing  Wheat,  pp.  40,  figs.  25. 

How  Insects  Affect  Health  in  Rural  Districts,  pp.  20,  figs.  16. 

Silk  Worm  Culture,  pp.  32,  figs.  15. 

The  Control  of  the  Coddling  Moth,  pp.  24,  figs.  4. 

Scale  Insects  and  Mites  on  Citrus  Trees,  pp.  43,  figs.  34. 

Insects  Injurious  in  Cranberry  Culture,  pp.  32,  figs.  12. 

Information  concerning  the  Cotton  Boll  Weevil,  pp.  31,  figs.  8. 

The  Cotton  Boll  Worm,  pp.  24,  figs.  7. 

Usefulness  of  the  Toad,  pp.  16. 

Reindeer  and  Caribou,  pp.  14,  pis.  7. 

Bird  Day  in  the  Schools,  pp.  4. 


24  INTRODUCTION 

The  Hop  Plant  Louse,  pp.  7,  figs.  6. 

The  Army  Worm,  pp.  5,  figs.  3. 

The  Carpet  Beetle,  or  Buffalo  Moth,  pp.  4,  fig.  1. 

Canker  Worms,  pp.  4,  figs.  4. 

Mosquitoes  and  Fleas,  pp.  6. 

The  Strawberry  Weevil,  pp.  7,  figs.  4. 

The  Ox  Warble,  pp.  10,  figs.  10. 

The  Pear  Slug,  pp.  7,  figs.  4. 

The  Fruit-tree  Bark-Beetle,  pp.  8,  figs.  4. 

The  Striped  Cucumber  Beetle,  pp.  7,  figs.  2. 

The  Larger  Apple  Tree  Borers,  pp.  12,  figs.  3. 

House  Ants,  pp.  4,  figs.  3. 

House  Flies,  pp.  8,  figs.  8. 

The  True  Clothes  Moth,  pp.  8,  figs.  3. 

The  Common  Squash  Bug,  pp.  5,  figs.  3. 

How  to  Distinguish  the  Different  Mosquitoes  of  America,  pp.  8. 

The  Bed-bug,  pp.  8,  figs.  3. 

The  House  Centipede,  pp.  4,  figs.  2. 

The  Silver  Fish,  pp.  4,  figs.  2. 

Cockroaches,  pp.  15,  figs.  5. 

The  Peach  Tree  Borer,  pp.  6,  fig.  1. 

Four  Common  Birds  of  the  Farm  and  Garden,  pp.  14,  figs.  4. 

The  Meadow  Lark  and  Baltimore  Oriole,  pp.  12,  figs.  2. 

Asparagus  Beetles,  pp.  12,  figs.  6. 

Insects  Injurious  to  Beans  and  Peas,  pp.  28,  figs.  17. 

The  Food  of  Nestling  Birds,  pp.  26,  figs.  14. 

Smyrna  Fig  Culture  in  the  United  States,  pp.  28,  figs.  15. 

How  Birds  Affect  the  Orchard,  pp.  14,  figs.  5. 

Insects  as  Carriers  and  Spreaders  of  Disease,  pp.  16,  figs.  15. 

The  San  Jose  Scale:  Home  and  Natural  Enemies,  pp.  20,  figs.  9. 

Insects  Injurious  to  Hardwood  Forests,  pp.  16,  figs.  17. 

Audubon  Societies  in  Relation  to  the  Farmer,  pp.  14,  figs.  4. 

Some  New  Facts  about  the  Migration  of  Birds,  pp.  16,  figs.  2. 

A  monthly  list  of  publications  by  the  United  States  Government 
may  be  had  free  of  charge  by  sending  the  request  to  the  Secretary 
of  Agriculture,  Washington,  D.  0. 


CLASSIFICATION 


25 


CLASSIFICATION 

For  the  sake  of  convenience  in  discussing  the  character- 
istics of  animals  the  entire  kingdom  is  divided  into  sub- 
kingdoms,  classes,  orders,  families,  and  species,  as  given  in 
the  following  outline.  It  is  not  intended  that  this  incom- 
plete table  of  classification  should  be  memorized,  but 
rather  that  the  pupils  should  become  familiar  with  it  as 
indicated  in  the  practical  questions  by  constant  reference 
to  it  throughout  the  term. 

SUBKINGDOM  I.  PnoTOz5'A  (first  animals) :  Single-celled 
aquatic  animals  of  microscopic  size.  Ameba 
and  Paramcecium  (Figs.  211,  209). 

SUBKINGDOM       II.   PORIF'ERA   (pore  bearers):  Sponges. 

SUBKINGDOM  III.  COSLENTERA'TA  (hollow  within):  Aquatic 
mostly  marine  animals  having  but  one  inter- 
nal cavity.  Jellyfish,  coral  builders,  and 
hydroids  (Figs.  203,  199). 

SUBKINGDOM  IV.  PLA"TYHELMIN'THES  (flatworms) :  Worms  with 
flattened  bodies  and  no  cavity  surrounding 
the  alimentary  canal.  Tapeworms  and 
liver  fluke  (Fig.  184). 

SUBKINGDOM  V.  NEMATHELMIN'THES  (thread  worms):  Round 
worms  with  no  external  evidence  of  seg- 
ments. Horsehair  worm  and  vinegar  eel 
(Fig.  183). 

SUBKINGDOM  VI.  TROCHELMIN'THES  (wheel  worms):  Minute 
aquatic  worms  with  cilia  about  the  mouth. 
Rotifer. 

SUBKINGDOM  VII.  MOLLUSCOI'DA  (like  a  mollusk) :  Aquatic 
worms  usually  living  in  colonies.  Sea  mats. 

SUBKINGDOM  VIII.  ECHINODER'MATA  (spiny  skinned) :  Marine 
radiate  forms  often  covered  with  spines. 
Starfish  and  sea  urchin  (Figs.  187,  190). 


26  INTRODUCTION 

SUBKINGDOM     IX.   ANNULA'TA   (with  rings):  Worms  with  seg- 
ments  apparent   externally.     Earth   worm 
and  leech  (Figs.  178,  179). 
SUBKINGDOM       X.   MOLLUS'CA  (soft):  Soft-bodied  forms  usually 

with  a  shell.     Oysters,  snails,  slug,  squid. 
SUBKINGDOM     XL   ARTHRO'PODA  (jointed  feet) :  Segmented  forms 

with  jointed  legs.     Crabs,  beetles,  wasps. 

Class  1.  Crusta'cea  (crust) :  Arthropoda  with  head  and  thorax 
fused  and  usually  a  hard  outer  skeleton.  Crayfish  (Fig.  155), 
lobster,  pill  bug  (Fig.  164). 

Class  2.    Myria'poda   (thousand-footed) :  Forms  with  air  tubes 
throughout  the  body  and  numerous  legs.     Centipeds    (Fig. 
152),  millepeds  (Fig.  153). 
Class  3.   Arach'nida  (spider) :  Forms  with  usually  four  pairs  of 

legs  and  no  antennae.     Spiders,  scorpions  (Figs.  144-151). 
Class  4.   Insec'ta  (cut-in) :  Forms  with  body  showing  three  dis- 
tinct parts  called  head,  thorax,  and  abdomen  ;  and  breathing 
by  means  of  tubes  ramifying  among  the  tissues  and  opening 
on  the  lateral  aspect  of  the  body  (Figs.  9,  10). 
Order  a.  Ephemer'ida  (lasting  one  day) :  Forms  with  two  unequal 
pairs  of  wings,  no  mouth  parts,  and  two  or  three  filaments 
projecting  from  the  end  of  the  abdomen.     May  fly  (Fig.  139). 
Order  b.   Odona'ta  (tooth) :  Forms  with  four  nearly  equal  mem- 
branous wings.     Dragon  flies,  damsel  flies  (Figs.  140,  141). 
Order  c.    Orthop'tera    (straight-winged) :   Forms   usually  with 
four  wings,  the  hinder  ones  being  thin  and  overlapped  by  the 
thick  fore  wings  when  at  rest.     Grasshoppers,  crickets,  cock- 
roaches (Figs.  11,  13). 

Order  d.  Hemip'tera  (half-winged) :  Forms  which  take  food  by 
sucking  only.  Bedbug,  cicada,  plant  lice,  scale  insects 
(Figs.  98,  107). 

Order  e.  Neurop'tera  (nerve-winged) :  Forms  with  two  pairs 
of  membranous  net-veined  wings.  Dobson  or  hellgramite 
(Fig.  138). 

Order  f.  Lepidop'tera  (scale-winged) :  Forms  with  two  pairs 
of  wings  covered  with  overlapping  scales.  Butterflies, 
moths,  millers. 


CLASSIFICATION  27 

Order  g.  Dip'tera  (two-winged) :  Forms  with  only  one  pair  of 
wings  and  behind  them  a  pair  of  short-knobbed  processes, 
the  halteres.  Flies  and  mosquitoes. 

Order  h.  Coleop'tera  (shield-winged) :  Forms  with  a  pair  of  horny 
wing  covers  and  a  single  pair  of  membranous  wings.  Beetles. 
Order  i.  Hymenop'tera  (membrane-winged) :  Forms  with  two 
pairs  of  membranous  wings,  mouth  parts  for  both  biting  and 
sucking,  and  the  female  usually  with  a  sting,  pierce,  or  saw. 
Ants,  bees,  wasps  (Figs.  32,  36). 

SUBKINGDOM  XII.  PHOTO  CHORD  A'TA  (first  cord) :  Marine  animals 
forming  a  connecting  link  between  the  ver- 
tebrates and  invertebrates.  Sea-squirts, 
lancelet. 

SUBKINGDOM  XIII.   VERTEBRA'TA    (turning) :  Forms  with  a  skele- 
tal axis  and  a  dorsal  nerve  cord  whose  an- 
terior end  is  dilated  into  a  brain. 
Class  1.   Pisces  (fish) :  Aquatic  cold-blooded  forms  with  gills  and 

usually  paired  fins,  but  not  legs. 

Class  2.   Amphib'ia  (both  lives):   Cold-blooded   forms  without 
scales,  usually  with  two  pairs  of  legs,  and  breathing  by  gills  in 
early  life.     Frogs,  salamanders,  toads  (Figs.  230,  231). 
Class  3.  Reptll'ia   (to  creep):    Cold-blooded  forms  with  scales 

and  lungs.     Snakes,  lizards,  turtles. 

Class  4.   A'ves  (birds) :  Warm-blooded  vertebrates  with  feathers. 
Class  5.   Mamma'lia  (with  breasts) :  Hairy  vertebrates  suckling 
their  young.     Dog,  monkeys,  man. 
Order  a.   Monotre'mata  (single  opening) :  Egg-laying  mammals. 

Duck  mole,  spiny  ant-eater  (Figs.  297,  300). 
Order  b.   Marsupia'lia    (pouch) :  Mammals  whose  young  at 
birth  are  very  small  and  immature  and  are  therefore  placed 
in  an   abdominal  pouch  to  be  nourished    several  weeks. 
Opossums,  kangaroos  (Figs.  299,  298). 
Order  c.   Insectlv'ora  (insect  eaters) :  Mammals  living  largely  on 

insects.     Shrews,  moles  (Fig.  311). 

Order  d.  Edenta'ta  (without  teeth) :  Forms  in  which  the  teeth 
are  often  wanting  and  if  present  there  is  no  enamel.  Sloths, 
ant-eaters. 


28  INTRODUCTION 

Order  e.   Chirtip'tera  (hand- winged) :  Forms  adapted  for  flight. 

Bats,  flying  foxes  (Fig.  310). 
Order  f.   Roden'tia   (gnawing):  Mammals  having  usually  two 

elongated  chisel-like  incisors  in  each  jaw.     Rabbits,  squirrels, 

mice,  rats  (Fig.  309). 
Order  g.   Ceta'cea    (whale):     Marine   mammals  with   fishlike 

body  and  no  hind  limbs.     Whales,  porpoises,  dolphins. 
Order  h.   Siren'ia  (siren) :  Aquatic  forms  with  no  hind  limbs. 

Sea  cow. 
Order  i.    Ungula'ta    (bearing  hoofs):  Mammals  which   have 

hoofed  feet.     Horse,  cow,  pig. 
Order  j.   Carnlv'ora   (flesh-eating):  Mammals  living  on  flesh 

and  with  strong  canine  teeth  and  claws.     Dogs,  cats,  wolves, 

foxes. 
Order  k.   Primates  (first) :  Mammals  with  thumb  opposable  to 

the  other  digits.     Lemurs,  monkeys,  man. 

A  glance  at  the  above  outline  shows  that  the  entire  ani- 
mal kingdom,  consisting  of  a  half  million  species,  is  divided 
into  thirteen  subkingdoms  sometimes  called  phyla  or 
branches.  Each  of  these  is  composed  of  several  classes, 
but  in  most  cases  the  names  of  the  classes  are  not  given. 
The  divisions  of  the  classes  are  designated  orders  which 
in  turn  are  divided  into  families.  A  family  is  composed 
usually  of  several  genera,  and  each  genus  is  still  further 
divided  into  species. 

Linnaeus  of  Sweden  invented  the  system  of  binomial 
nomenclature,  in  accordance  with  which  the  name  of  every 
plant  or  animal  is  composed  of  two  parts,  the  generic 
which  is  a  noun,  and  the  specific,  which  is  an  adjective. 
Thus,  the  house  cat  is  called  Fells  domestica;  the  lion 
Felis  leo  ;  the  dog,  Canis  familiaris;  the  wolf,  Canis  latrans; 
the  red  squirrel,  Sciurus  hudsonicus ;  the  gray  squirrel, 
Sciurus  carolinensis.  Animals  of  the  same  genus  but  of 


CLASSIFICATION  29 

different  species  resemble  each  other  much  closer  than  do 
animals  of  two  different  families,  and  still  fewer  characters 
are  common  to  animals  belonging  to  different  orders. 
Thus,  the  horse,  Equus  caba'lus,  and  the  ass,  Equus  asi- 
nuSj  differ  chiefly  as  to  the  tail  and  ears  only.  Both  belong 
to  the  order  Ungulata  and  family  Equidce.  The  cow,  Bos 
taurus,  of  the  same  order  but  of  the  family  Bovidce,  differs 
much  from  the  horse  and  ass  in  possessing  shorter  legs  with 
two  toes,  a  pair  of  horns,  and  no  upper  incisor,  or  canine 
teeth.  The  black  bear,  Ursus  americanus,  presents  great 
contrast  in  structure  to  the  above  animals  and  is  therefore 
placed  in  another  order,  Carnivora.  It  feeds  on  flesh,  has 
teeth  adapted  to  cutting  instead  of  grinding,  and  claws  in 
place  of  hoofs. 

Since  a  fish  resembles  the  above  animals  in  having  a 
back  bone,  a  brain,  and  nerve  cord  on  the  dorsal  side  it  is 
placed  in  the  same  subkingdom,  Vertebrata,  but  must  be 
assigned  to  another  class,  Pisces,  on  account  of  the  absence 
of  hair,  limbs,  lungs,  and  other  features  common  to  the 
mammals. 


PART  I 

ARTHROPODA:    SEGMENTED    FORMS    WITH 
JOINTED  LEGS 

1.   ORTHOPTERA 

THE  majority  of  the  species  of  animals  belong  to  the 
branch  Arthropoda.  A  feature  distinguishing  this  group 
from  all  other  invertebrates  is  the  presence  of  jointed  legs. 
These,  however,  may  be  absent  in  a  few  forms  leading  a 
parasitic  life  (Fig.  150) .  Of  the  four  classes  of  Arthropoda, 
the  insects,  numbering  over  three  hundred  thousand 


FIG.  6.  —  A,  Long-horned  grasshopper;  B,  Locust;  a,  antennae;  o,  ovipositor. 

species,  are  the  most  important  because   among  them  are 
found  man's  greatest  enemies  as  well  as  valuable  helpers. 

Locusts 

The  locusts,  commonly  called  grasshoppers,  include  about 
three  hundred  different  species,  but  only  three  or  four  kinds 
are  easily  found  in  any  one  locality.    Only  the  short-horned 
30 


OKTHOPTEltA 


31 


grasshoppers  (Acndfidcs) ,  which  means  those  having  an- 
tenna half  the  length  of  the  body,  or  less,  are  true  locusts. 
Those  with  antenna  nearly  as  long  as  the  body,  or  longer, 
are  the  true  grasshoppers  (Locustidce) .  Such  is  the  katy- 
did (Microcentrwn  retinervis),  which  is  more  than  an  inch 
long  and  has  wings  so  veined  and  colored  as  to  resemble  a 
green  leaf. 

Habits.  —  In  most  cases  the  eggs  of  the  locust,  number- 
ing from  ten  to  a  hundred  and  having  somewhat  the  form 
of  grains  of  wheat,  are 
laid  during  July  or  Au- 
gust in  the  soil.  They 
are  held  together  in  ir- 
regular masses  by  a  ce- 
ment. The  majority  of 
the  species  pass  the 
winter  in  the  egg  state, 
but  the  large  American 
locust,  or  bird  grass- 
hopper of  our  southern  states,  hibernates  as  an  adult.  The 
young  locusts,  called  nymphs,  emerge  from  the  eggs  hidden 
a  half  inch  or  more  in  the  soil,  during  early  summer. 
Forms  from  a  fourth  of  an  inch  to  a  half  inch  long  and 
wingless  may  be  found  in  abundance  in  the  grassy  fields 
during  May  and  June.  If  some  of  these  are  caught  and 
fed  with  grass  daily  for  a  week  or  two  the  observer  may 
have  the  rare  pleasure  of  seeing  the  insect  molt,  i.e.,  shed 
its  skin.  Most  insects  molt  during  their  growth  period 
from  three  to  six  times. 

After  the  locust's  first  molt   the  wing  pads  appear  as 
tiny  projections,  and  after  the  third  molt  they  are  quite 


FIG.  7.  — Locust  about  two  weeks  old.    Pho- 
tograph twice  natural  size. 


32 


ARTHROPODA 


conspicuous,  but  they  do  not  serve  for  flight  till  after  the 
last  molt,  when  the  insect  is  said  to  have  completed  its 
transformation  from  the  nymph  to  the  adult  state.  In 
most  regions  the  mature  insects  may  be  found  in  grassy 
fields  from  July  till  frost  appears. 

External  Features. — The  food  of  the  locusts  is  almost 
any  kind  of  green  herbs,  which  they  bite  off  with  a  pair  of 
hard  lateral  moving  mandibles. 
An  examination  of  the  mouth 
region  shows  an  upper  lip  or 
labrum  covering  the  front  side 
of  the  mandibles,  which  are 
easily  recognized  by  their  hard- 
ness and  serrated  inner  mar- 
gins. Behind  these  is  a  pair 
of  maxillce  divided  into  three 
lobes,  the  outer  and  longer  of 
which  is  the  feeler,  or  palpus. 
Next  in  order  is  the  lower  lip,  or 
labium,  apparently  composed  of 
two  lateral  halves,  each  bearing 
a  palpus. 


'•JLS n 


n 


«,  r~.r —     Most  biting  insects 

FIG.    8.  — Mouth  parts  of  a  locust.  . 

,  antenna;   I,  labrum  turned  for-     present  mouth  parts  similar  to 

these.     The    mosquitoes    and 


\vard  to  expose  the  mandibles,  m; 

n,   maxilla   reflected ;    6,  palpi  of 

the    maxilla ;    t,    labium.      Twice     some  flies  and  bugS  have 

natural  size.    Drawing  by  Reese.          .  .  .    . 

ing  but  not  biting  mouth  parts. 

The  locust's  body  is  divided  into  three  parts:  the  head, 
bearing  a  pair  of  many-jointed  antennae;  the  thorax,  sup- 
porting three  pairs  of  legs  and  two  pairs  of  wings,  the  an- 
terior of  which  are  parch  men  tlike  and  serve  to  cover  the 
posterior  which  are  membranous  and  folded  longitudinally 


ORTHOPTERA 


38 


like  a  fan  when  the  insect  is  at  rest;  and  the  abdomen,  which 
in  the  female  terminates  in  two  pairs  of  sharp-hooked 
spines  forming  the  ovipositor  or  egg-depositing  apparatus. 
The  thorax  and  abdomen  are  composed  of  ringlike  portions, 
called  somites,  of  which  the  three  in  the  thorax  are  named 
prothorax,  mesothorax,  and  metathorax.  The  part  of  the 
somite  on  top  is  the  tergum,  that  underneath  is  the 
sternum,  and  on  the  sides  are  the  pleura.  Eleven  somites 


FIG.  9.  — Locust  with  the  left  wing  w  cut  off  near  the  base,  a,  antennae  ;  d,  ear  ; 
e,  compound  eye  ;  /,  femur  ;  J,  labrum  ;  m,  maxilla  ;  n,  front  leg  of  right  side ; 
o,  mandible ;  pt  palpus  of  right  maxilla ;  r,  tarsus ;  s,  segments  of  the  abdo- 
men ;  tt  tibia ;  tr,  trochanter ;  photograph,  natural  size. 

are  present  in  the  abdomen,  and  the  dorsal  (upper)  and 
ventral  (under)  part  of  each  is  composed  of  a  single  plate 
named  the  tergite  and  sternite,  respectively.  The  sternites 
of  the  last  three  somites  are  wanting  in  the  female. 

Each  leg  is  composed  of  a  short  proximal  segment,  the 
trochanter;  a  second  segment,  stout  and  long,  known  as  the 
femur;  a  third  segment,  long  and  slender,  called  tibia,  and 
a  terminal  portion  made  of  several  pieces  forming  the 


34 


ARTHROPODA 


tarsus.  Between  the  two  claws  at  the  end  of  the  tarsus 
is  a  little  pad,  the  pulvillus,  which  enables  the  animal  to 
walk  on  smooth  surfaces.  Directly  behind  the  bases  of 
the  antennae  are  the  two  large  compound  eyes  composed 
of  hundreds  of  cones  whose  ends,  called  facets,  may  be  seen 
on  the  surface  with  a  good  hand  lens  or  low  power  of  the 
compound  microscope.  Three  ocelli,  or  simple  eyes,  well 
seen  with  a  hand  lens,  are  also  present.  As  hi  most  insects, 

the  median  one  is  between 

the  antennae  and  the  lateral 
ones  just  in  front  of  the 
compound  eyes.  The  ear 
is  a  circular  opening  covered 
by  membrane  on  the  side 
of  the  first  abdominal  seg- 
ment. On  the  lateral  aspect 
of  each  of  the  eight  anterior 
segments  of  the  abdomen 
and  the  two  posterior  seg- 
ments of  the  thorax  is  a 
minute  opening  barely  vis- 

Photograph  of  a  spiracle  with  ible  to  the  naked  eye.  It 
is  the  spiracle,  which  admits 
air  to  a  tube  branching 
profusely  among  the  tissues  for  the  purpose  of  supplying 
all  parts  with  oxygen  and  carrying  away  the  carbon 
dioxide  formed  in  every  region  of  an  animal's  body. 
These  ramifying  tubes,  called  trachece,  are  common  to  all 
insects  and  a  few  other  Arthropoda. 

Destruction  of  Crops.  —  Locusts  have  always  been  a 
great  pest  to  man,  as  may  be  inferred  from  the  destructive 


FIG.  10. 

Its    tracheae    removed  from   an  insect. 
«,  spiracle.    Three  times  natural  size. 


ORTHOPTERA  35 

powers  of  the  insects  frequently  mentioned  in  the  Scrip- 
tures. Williamson's  History  of  Maine  says:  "  In  1749 
and  1754  they  were  very  numerous;  no  vegetables  escaped 
these  greedy  troops;  they  even  devoured  the  potato  tops; 
and  in  1743  and  1756  they  covered  the  whole  country  and 
threatened  to  devour  every  green  thing.  Indeed,  so  great 
was  the  alarm  they  occasioned  among  the  people,  that 
days  of  fasting  and  prayer  were  appointed."  In  1838 
the  common  red-legged  locust  (Melanoplus  femur-rubrum) 
was  so  abundant  in  parts  of  Maryland  that  the  negroes 
were  employed  to  drive  them  from  the  gardens  with  rods. 
The  most  injurious  species  occur: ing  in  this  country  is 
the  Rocky  Mountain  locust  (Melanoplus  spretus)  or  mi- 
gratory locust.  From  1874  to  1876  they  damaged  west- 
ern agriculture,  especially  in  Kansas,  Colorado,  Nebraska, 
and  Missouri,  to  the  extent  of  over  two  hundred  million 
dollars.  The  government  appointed  a  special  committee 
to  devise  a  remedy  to  exterminate  or  check  the  pest,  and 
numerous  plans  for  destroying  the  eggs,  young,  and  adults 
were  brought  forward.  In  Minnesota  one  farmer  col- 
lected during  the  latter  part  of  June  about  eight  hundred 
bushels,  by  dragging  with  horses  across  the  grain  fields 
after  dark  a  large  box  with  the  front  side  removed  so  as  to 
allow  the  insects  to  tumble  in.  Another  farmer  in  the 
same  manner  captured  four  hundred  bushels.  Some 
counties  paid  a  reward  for  locusts  collected  and  killed. 
In  1875  Nicollet  County,  Minnesota,  paid  a  dollar  per 
bushel  for  25,053  bushels  of  locusts.  Fortunately  the 
insects  appear  in  large  numbers  only  at  intervals  of  from 
five  to  twenty  or  more  years,  according  to  the  condition  of 
the  weather  and  the  presence  of  enemies.  The  Rocky 


36 


ARTHROPODA 


Mountain  locust  is  always  present  in  greater  or  less  num- 
bers in  Montana  and  parts  of  Dakota,  Wyoming,  Colorado, 
Utah,  Idaho,  and  Oregon.  On  certain  occasions  swarms 
of  many  millions  migrate  to  the  adjacent  states,  being 
driven  by  the  wind  as  they  hold 
the  wings  expanded,  but  they 
have  never  been  found  east  of  the 
Mississippi  River.  The  Carolina 
locust  (Dissosteira  Carolina),  the 
large  gray  species  frequenting  the 
roadside  everywhere  in  late  sum- 
mer, and  recognized  by  its  yellow- 
bordered  hind  wings,  seldom  be- 
comes so  numerous  as  to  cause 
much  damage. 

The  Black  Cricket 

The  short-winged  black  cricket 
(Gryllus  abbreviatus)  is  a  common 
autumn  insect  in  every  pasture 
and  may  frequently  be  found  un- 
der boards  and  stones  as  late  as 
December.  The  female  is  distin- 
guished from  the  male  by  the  long 
ovipositor  projecting  from  the  end 
Natural  of  the  abdomen,  through  which  eggs 
pass  into  holes  made  in  the  ground. 
Here  they  remain  from  fall  until  spring,  when  the  little 
crickets  emerge  in  the  nymph  stage  without  wings.  The 
crickets  are  celebrated  for  their  high-pitched  chirping, 
produced  by  the  male  only,  by  elevating  over  the  back 


ius  abbreviates). 


ORTHOPTEBA 


87 


and  rubbing  together  the  two  wing  covers  or  outer  wings 
on  the  bases  of  which  are  roughened  portions.  The  rate 
of  chirping  is  according  to  the  temperature  of  the  air. 

,   chirps    per  minute— 40 
The  formula,  temperature  =  50  H —  — r — 

will  enable  any  one  to  know  how  high  the  mercury  stands. 
The  sounds  made 
by  the  male  locusts 
are  produced  in 
some  species  by  rub- 
bing the  hind  legs 
against  the  outer 
wings  and  in  others 
by  rubbing  together 
the  upper  surface 
of  the  front  edge  of 
either  hind  wing  and 
the  under  surface 
of  a  wing  cover.  All 
the  high  shrill  notes 
of  the  upland  heard 
on  dull  days  and  in 
the  evening  are  pro- 
duced by  the  crick- 
ets, grasshoppers,  or 
locusts  on  whose  legs 
or  wings  the  rough 

Surfaces  OCCUr.  The  FIG.  12.  —  Walking  stick  (JXapheromera  femorata). 
cricketfeedsOngraSS,  Photograph,  natural  size. 

clover,  or  almost  any  other  kind  of  vegetation.  There  are 
numerous  species  of  the  cricket  family  (GrylUdce) . 


38 


ARTHROPODA 


Walking  Sticks.  —  The  walking  sticks  (Phasmidce)  are 
so  called  because  of  their  resemblance  to  a  twig.  Our 
common  one  (Diapheromera  femorata)  occasionally  be- 
comes so  numerous  as  to 
strip  all  the  foliage  from 
acres  of  forests. 

Cockroaches.  —  Of  the 
four  common  species  of 
roaches  (Blattidce)  two  are 
household  pests  imported 
from  Europe.  The  large 
black  roach  (Periplaneta 
orientalis)  frequents  sugar 
refineries,  slaughter- 
houses, and  bake-shops. 
The  Croton  bug  (Ectobia 
germanicd)  is  common  in 
kitchens.  Roaches  are 
omnivorous.  They  feed 
clothing,  bookbind- 
breadstuffs,  and 
living  insects,  such  as 
bedbugs.  Ships  some- 
times become  so  badly 
infested  with  roaches  that 
the  sailors  wear  gloves 
while  sleeping  to  prevent 


on 


FIG.  13.  —  Large  black  roach.     Photograph 
nearly  twice  natural  size. 


the  insects  from  gnawing 
their  fingers.  The  eggs  are  inclosed  in  bean-shaped  packets 
and  may  be  seen  hanging  fast  to  the  abdomen  of  the 
female  or  found  in  protected  crevices. 


DIPTERA 


39 


2.   DIPTERA 

This  order  includes  all  the  true  flies.  They  are  the  only 
insects  except  the  male  scale  insects  and  a  few  May  flies 
which  have  but  two  wings.  About  forty  thousand  species 
are  known.  Their  study  is  of  great  importance  because 
among  them  are  some  of  our  most  deadly  enemies,  while 
others  are  our  best  friends. 

Mosquitoes 

The  mosquitoes  have  a  typical  life  history,  and  as  they 
are  in  all  parts  of  the  world  even  as  far  north  as  Lapland 
and  Greenland,  the  pupils  will  find  no  difficulty  in  secur- 
ing specimens.     Their  habits  may  be 
studied   from  April   to  November  by 
securing  the  eggs  or  larvae  and  plac- 
ing them  in  a  jar  of  water  with  some 
algae   (frog  spittle,  etc.) .      These  may 
be  found  in  quiet  pools  of  water  not 
inhabited  by  fish.      A  rain  barrel  or  a 
pail  of  water  that  has  remained  out  of 
doors  a  few  nights  is  apt  to  contain 
them. 

Life  History.  —  The  eggs  of  the  com- 
mon species,  Culex,  are  laid  so  that  the 
two  or  three  hundred  stand  on  end 
and  stick  close  together,  forming  a 
grayish  floating  mass  nearly  a  quarter 
of  an  inch  long.  They  are  deposited  early  in  the  morn- 
ing and  often  hatch  within  a  day  into  minute  wrig- 
gling larvce  which  continue  to  grow  from  seven  to 


FIG.  14.  —  Eggs  of  mos- 
quitoes. A,  Culex;  B, 
Anopheles  photograph- 
ed on  the  water,  natu- 
ral size. 


40  ARTHROPODA 

fourteen  days  and  attain  a  length  of  a  half  inch  or  more. 
If  the  eggs  are  laid  in  late  fall  they  may  not  hatch  until 
the  next  spring.  The  larva  rises  to  the  top  of  the  water 
at  intervals  to  breathe  through  a  tube  projecting  from  the 
tail  end.  This  tube  extends  throughout  the  body  and 
thereby  supplies  the  tissues  with  oxygen. 

After  three  molts  the  pupa  stage  is  assumed  and  lasts 
from  two  to  five  days,  depending  upon  the  temperature, 


FlG.  15.  —  Three  pupae  and  two  larvae  of  mosquitoes  at  the  surface  of  the  water 
breathing.    Photograph  from  life,  twice  natural  size. 


during  which  air  is  admitted  to  the  body  by  two  earlike 
organs  on  the  thorax.  In  the  next  transformation  the 
adult  mosquito  emerges  from  a  slit  in  the  back  of  the  pupal 
skin  and  is  ready  in  a  few  minutes  to  fly. 

Food.  —  In  its  method  of  taking  food  the  mosquito 
differs  from  the  locust,  as  it  has  no  biting  apparatus  but  a 
piercing  and  sucking  organ  forming  the  proboscis.  The 
labrum  (upper  lip)  and  Idbium  (lower  lip)  form  a  tube  inclos- 
ing the  pair  of  hairlike  mandibles  and  maxillce  in  addition 
to  a  tubular  stylet,  the  hypopharynx,  an  outgrowth  from 
the  floor  of  the  mouth.  The  hypopharynx  lies  against 


DIPTERA 


the  labrum  so  as  to  form 
a  canal  through  which 
the  food  passes  (Fig.  18) . 
These  several  partsmay  be 
seen  under  the  microscope 
by  placing  the  head  of  a 
female  in  a  drop  of  water 
on  a  glass  slide  and  press- 
ing lightly  on  the  cover 
glass  laid  over  it.  The 
favorite  food  of  the  female 
is  blood  of  any  of  the 
vertebrates.  The  male 
never  bites  and  may  be 
distinguished  from  the 
female  by  the  antennae 
which  are  much  more 
richly  feathered.  The 
two  chief  genera  of  the 
four  hundred  species  of 
mosquitoes  are  Culex  and 
Anopheles.  In  the  female 
of  Culex,  the  palpi  are 
not  more  than  a  fourth 
as  long  as  the  proboscis, 
while  in  Anopheles,  the 
proboscis  and  palpi  are 
almost  equal.  The  palpi 
are  quite  long  in  the 
males  of  both  genera. 
When  at  rest,  the  pro- 


42 


ARTHKOPODA 


boscis,  head,  thorax, 
and  abdomen  of  Ano- 
pheles are  all  in  a 
straight  line,  and  the 
body  is  held  oblique 
to  the  surface  to  which 
the  insect  adheres, 
apparently  trying  to 
stand  on  its  head. 
Members  of  the  genus 
Culex  have  a  bend  at 
the  juncture  of  the 
abdomen  and  thorax 
and  hold  the  body  par- 
allel with  the  surface 
to  which  they  cling. 
Agents  of  Disease.  —  About  the  year  1899  it  was  clearly 
shown  that  the  several  species  of  Anopheles  are  the  agents 


FIG.  17. —  Photograph  of  Anopheles,  the  agent 
transmitting  malaria.  The  antenna?  are  curved 
and  the  upper  two  of  the  three  straight  projec- 
tions from  the  head  are  the  palpi.  Enlarged 
three  diameters. 


FIG.  18.  —  Diagrammatic  vertical  section  of  the  head  and  proboscis  of  a  mosquito. 
I,  labium  bent  as  when  the  other  parts  pierce  the  skin  ;  p.  pumping  organ  ;  o, 
hypopharynx  through  which  is  a  channel  for  the  exit  of  the  secretions  of  the 
poison  and  salivary  glands  pn  and  s  ;  d,  exit  for  poison  and  saliva  ;  m,  maxilla  ; 
ma,  mandible  ;  la,  labrurn  below  which  is  the  channel  conducting  the  food  from 
the  inlet  at  n ;  st,  stomach.  Drawing  by  Reese. 

in  transmitting  the  malaria  from  man  to  man.    When  the 
mosquito  feeds  on  the  blood  of  a  malaria  patient  thou- 


DIPTEKA 


48 


sands  of  the  germs, 
Hcemameba  terti- 
ana,  are  taken  into 
its  stomach,  from 
which  they  migrate 
to  the  salivary 
glands  (Fig.  18), and 
thence  are  forced 
with  the  saliva  into 
persons  bitten  later. 
The  saliva  is  ejected 
by  the  mosquito 
to  break  up  the  red 
blood  cells  which 
are  too  large  to  pass 
through  its  pro- 
boscis. The  itch- 
ing and  painful 
effect  of  the  bite  are 
due  to  the  poison 
injected  along  with 
the  saliva. 

Lately  it  has  been  shown  that  yellow  fever  is  trans- 
mitted by  mosquitoes  and  in  no  other  way.  The  only 
offender  is  Stegomyia  fasciata.  It  is  probable  that  these 
insects  are  responsible  for  some  other  diseases  affecting 
man. 

Destruction  of  Mosquitoes.  —  On  account  of  the  fact  that 
the  mosquitoes  are  responsible  for  more  sickness  and 
death  annually  than  all  the  wars  of  the  world,  efforts  are 
being  made  to  exterminate  them  by  draining  the  stagnant 


FIG.  19.  —  Photograph  of  heads  of  mosquitoes.  A, 
male ;  -B,  female ;  a,  antenna  ;  pi,  palpus ;  pr, 
proboscis. 


AETHROPODA 


FIG.  20.  — Culex,  male   and  female.    Photograph, 
three  times  natural  size. 


ponds  and  marshes. 
Where  draining  is 
impossible  the  larvse 
have  been  killed  by 
pouring  kerosene 
over  the  water,  which 
prevents  them  from 
getting  any  air.  A 
quart  of  the  oil  is 
sufficient  for  an  area 
of  five  hundred 

square  feet.  It  should  be  applied  every  two  weeks  during 
warm  weather.  Cuba  spent  a  hundred  thousand  dollars 
in  one  year  to  control 
the  mosquito  pest,  and 
as  a  result  Havana  was 
freed  of  yellow  fever  for 
the  first  time  within  a 
hundred  years.  Experi- 
ments conducted  in  my 
laboratory  show  that 
most  ponds  may  be  kept 
free  of  mosquitoes  by 
introducing  into  them 
newts,  blunt-nosed  sala- 
manders, fish,  or  dragon- 
fly larvse. 

The  crane  flies  resem- 


FlG.  21.  — Blood  corpuscles  of  a  patient  with 
malarial  fever.  Two  corpuscles  contain  the 
parasites.  Photograph,  enlarged  one  thou- 
sand diameters. 


ble  the  mosquitoes,  but 

most    of    them    are    much    larger    and    they    have    no 

scales  on  the  wings,  the  sure  mark  of  a  mosquito.    The 


DIPTERA 


45 


FIG.  22.  —  Wing  of  a  mosquito.    Photographed  through  the  microscope  to  show  the 
scales. 

crane  flies  are  easily  recognized  by  their  long  brittle  legs 
and  long  neck.  The  larvae 
of  many  species  do  some 
damage  among  the  roots  of 


House  Fly  (Musca 
Domestica) 

This  nuisance  is  found  in 
most  parts  of  the  entire  world. 
Recently  it  has  been  shown 
that  its  natural  breeding  place 
is  in  the  manure  thrown  out 

FIG.  23.  — Crane  fly.  Photograph,  nat-    of    horse    S tables.        The     hun- 
ural  size.  ,       ,  ,  . ,      , 

dred  or  more  eggs  deposited  at 

intervals  by  a  female,  hatch  in  from  six  to  twelve  hours 
into  white  pointed  larvae  called  maggots.       These  molt 


46 


ABTHBOPODA 


twice  and  attain  full  size  in  from  four  to  eight  days, 
whereupon  the  outer  skin  hardens,  swells  out,  and  turns 
brownish  to  form  cases  within  which  the  pupae  trans- 
form in  from  four  to  eight  days  into  the  adults. 

If  boards  of  health  would  compel  the  frequent  removal 
of  horse  manure  from  the  vicinity  of  towns  the  fly  nuisance 
might  be  greatly  abated.  About  one  fifth  of  the  soldiers 
in  the  national  encampment  in  1898  developed  typhoid 


FIG.  24. —  Common  fly,  its  pupa,  larva,  and  eggs.     Photograph,  twice 
natural  size. 

fever,  which  was  undoubtedly  transmitted  in  some  cases 
by  flies.  These  insects  visit  unclean  places  and  thus  carry 
the  germs  on  their  feet  to  distribute  them  later  as  they 
walk  about  over  our  food.  I  have  found  more  than  a  hun- 
dred germs  (bacteria)  clinging  to  the  feet  of  one  fly. 

The  house  fly  never  bites,  but  before  a  rain  the  stable 
fly  (stomoxys),  seen  in  large  numbers  on  the  cows,  enters 
the  house  and  frequently  bites  human  beings.  Other 
relatives  of  the  house  fly  are  the  blowfly  or  blue-bottle 


DIPTERA 


47 


fly,  which  lays  its  oval  white  eggs  on  decaying  meat, 
where  the  larvae  (maggots)  complete  their  growth  in  about 
ten  days;  the  screw-worm  fly,  usually  breeding  in  putre- 
fying flesh,  but  sometimes  in  sores  on  animals  and  even 
human  beings;  and  the  cabbage  fly,  whose  maggot  lives  in 
the  roots  of  young  cabbage  and  cauliflower  in  early  sum- 
mer, causing  great  loss  to  these  crops. 

Other  Important  Flies 

Tachina  Flies.  —  All  of  the  numerous  species  of  the 
Tachinas  are  beneficial,  as  their  larvae  feed  on  the  larvae 
of  harmful  insects  such  as  caterpillars 
and  cutworms.  The  surest  way  to 
secure  specimens  is  to  look  for  the 
minute  oval  eggs  glued  to  the  skin  of 
a  caterpillar,  which  should  be  fed  in 
a  box  containing  an  inch  or  two  of 

,-,  mi-      i»lAr  •  FlG-  25.  —  Photograph    of 

earth.      The  little  maggot  emerging       a  Tachina  fly.    Twice 

from    the    lower    side    of   each   egg 

penetrates  the  host  and  feeds  on  its  fatty  matter  a  week 


FIG.  26.  —  Photograph  of  four  eggs  of  a  Tachina  on  a  larva  of  a  Catalpa  moth. 
Natural  size. 

or  two,  after  which  it  comes  forth  and  remains  several  days 
on  or  near  the  surface  of  the  ground,  a  quiescent  pupa 


48  ARTHROPODA 

within  its  hardened  brown  skin.  In  the  mean  time  trans- 
formation to  the  adult  fly  occurs,  and  the  skin  is  then  rup- 
tured for  its  exit. 

Howard  says  he  has  seen  millions  of  the  army  worm  at 
work  and  not  a  single  individual  could  be  found  which  did 
not  bear  Tachina  eggs.  One  great  outbreak  of  the  army 
worm  hi  Alabama  in  1881  was  completely  frustrated  by 

the  Tachina  flies  and 
a  few  other  parasites. 
Syrphus  Flies.  — 
These  are  found 
among  the  flowers 
and  shrubbery  in  the 
bright  sunshine. 

FIG.  27.  — Syrphus  flies.     Photograph,  natural  size.     „,,  ,,          ., 

They  resemble     the 

bees  and  the  wasps,  though  many  of  them  are  as  small  as 
the  house  fly,  and  are  often  marked  with  orange  or  yellow- 
ish bands  on  the  abdomen.  The  larvae  of  some  species 
may  be  found  feeding  on  plant  lice,  while  others  live  on 
decaying  wood  and  manure.  At  least  one,  the  drone  fly 
(Eristalis  tenax),  breeds  in  decaying  flesh,  where  its  larva 
is  known  as  the  rat-tailed  maggot.  The  idea  prevalent, 
that  carcasses  of  animals  may  generate  swarms  of  bees, 
arose  from  the  fact  that  the  drone  fly  closely  resembles 
the  honey  bee.  The  story  of  Samson  in  the  Book  of 
Judges  relates  such  an  incident. 

Botflies.  —  The  several  species  of  these  are  parasites 
of  vertebrates.  The  botfly  of  the  horse  (Gastrophilus  equi) 
is  familiar  to  all  who  have  been  about  horses  in  late  summer 
and  noticed  a  large  fly  similar  to  a  honey  bee  depositing 
minute  yellowish  elongate  eggs  on  the  fore  legs  of  the  horse. 


DIPTERA 


49 


FIG.  28.  — Botfly  of  the  horse, 
larva  and  adult.  Natural  size. 
After  Selenka. 


Later  these  are  licked  off  by  the  animal  and  taken  into 

the   stomach,   where   they  develop  into  grublike   larvae. 

After  attaching  themselves  to  the 

walls  of   the   stomach,  they  are 

nourished  by  the  blood  and  lymph 

of   the  host   until  the  following 

spring,  when  they  pass  on  through 

the  canal,  burrow  into  the  ground, 

and    transform    into    the    adult 

about    two    weeks    later.     Bots 

are    sometimes     fatal     to     the 

horse. 

The  ox  warble  or  heel  fly  (Hypoderma  lineata)  is  a 
pest  to  cattle  raisers.  The  eggs  deposited  in  the  hair 
are  licked  off  by  the  cow,  and  immediately  hatching  pene- 
trate the  esophagus  to  wander  several  months  among 

the  tissues,  finally 
reaching  their  des- 
tination beneath 
the  skin  on  either 
side  of  the  back- 
bone. The  lumps 
in  these  regions  in 
spring  and  early 
summer  reveal  the 
presence  of  the  in- 
sect. In  late  sum- 
mer the  maggot 
emerges,  drops  to 
the  ground,  and  transforms  to  the  adult.  Stratton  estimates 
that  this  parasite  in  the  United  Kingdom  causes  a  loss  of 


FIG.  29.  —  Ox  warble  or  heel  fly.  a,  adult ;  i,  larva 
removed  from  beneath  the  skin  of  the  cow.  Nat- 
ural size.  From  Insect  Life. 


50 


ARTHROPODA 


forty  million  dollars  annually.  The  presence  of  these 
grubs  in  an  animal  produces  holes  in  the  hide  and  renders 
the  meat  along  the  back  unwholesome.  From  January  to 
June  fifty  per  cent  of  the  cattle  received  in  the  Union  Stock- 
yards at  Chicago  are  thus  affected. 

Hessian  Fly.  —  The  Hessian  fly  (Cecidomyia  destructor) 
is  familiar  to  most  agriculturists  through  its  ravages  on 
the  wheat  crop.  It  is  supposed  to  have  been  introduced 
into  this  country  on  the  straw  brought  over  by  the  Hessian 

troops  in  the  Rev- 
olutionary War. 
Specimens  for 
study  are  easily 
secured  by  examin- 
ing affected  wheat 
fields  in  May,  June, 
July,  November,  or 
December.  There 

FIG.  30.  — Photograph  of  the  Hessian  fly,  twice  natural        are       tWO       genera- 
size.    The  flaxseed  or  pupa  is  at  the  base  of  a  stalk        ,  •  rpr 
of  wheat  from  which  the  leaves  are  stripped  down.               1S  a  year. 

minute  reddish  eggs 

are  laid  in  the  spring  on  the  upper  surface  of  the  leaves, 
where  a  fortnight  later  they  hatch  into  wormlike  larvae. 
By  June  they  attain  a  length  of  a  fourth  of  an  inch,  and 
transform  to  the  flaxseed  or  pupa  between  the  leaves  and 
the  stem  at  its  base.  The  stalks  affected  are  in  an  in- 
clined or  brokendown  condition.  The  adult  fly  emerges 
from  the  pupa  case  in  August  or  September  ready  to  ovi- 
posit on  the  fall  crop  wherein  the  pupae  remain  during  the 
winter.  This  insect  annually  damages  the  wheat  crop  to 
the  extent  of  forty  millions  of  dollars. 


DIPTERA 


51 


Other  pests  closely  related  to  the  Hessian  fly  are  the 
wheat  midge,  feeding  upon  the  kernels  of  grain,  the  clover- 
seed  midge,  whose  larvse  destroy  the  growing  seed  of  the 
clover,  and  the  pear  midge,  feeding  in  young  pears. 

Though  the  word  "Diptera"  signifies  two  wings,  yet 
there  are  a  few  members  of  the  order  like  the  fleas  which 
have  lost  their  wings 
because  of  their  par- 
asitic habits.  The 
sheep  tick  dwelling 
in  the  wool  of  the 
sheep,  the  louse  par- 
asite on  the  honey 
bee  are  also  exam- 
ples of  wingless  flies. 

Nearly  all  of  the 
Diptera  have  a  com- 
plete metamorphosis,  i.e.,  exhibit  four  stages  in  their  life 
history.  Most  species  deposit  eggs,  but  a  few,  such  as  the 
flesh  flies,  bring  forth  their  young  alive.  The  larva  in  this 
order  is  an  active  wormlike  creature  which  in  some  species, 
such  as  the  mosquito,  buffalo  gnat,  and  horse  flies,  dwells 
in  the  water,  while  in  others  it  lives  in  decaying  matter  or 
is  parasitic  in  plants  or  animals.  The  larva  sheds  its  skin 
(molts)  two  or  more  times,  and  usually  the  skin  shed  last 
forms  a  kind  of  case  in  which  transformation  to  pupa  and 
from  pupa  to  adult  occurs.  The  life  of  the  adult  insects 
of  this  order  is  seldom  longer  than  a  few  weeks,  but  some 
species  such  as  the  house  fly  and  certain  mosquitoes  live 
in  a  dormant  state  for  several  months  during  the  cold 
season  and  become  active  in  the  spring. 


FIG.  31.  — Common  dog  or  cat  flea  (Pulex  serrati- 
ceps).    Photograph,  enlarged  thirty  diameters. 


52  ARTHROPODA 

3.   HYMENOPTERA 

The  members  of  this  order  are  readily  distinguished 
from  other  insects  by  the  presence  usually  of  four  scale- 
less  transparent  wings  of  which  the  hinder  pair  is  the 
smaller.  The  sting  present  at  the  end  of  the  abdomen  in 
the  females  of  many  species  is  a  structure  not  possessed  by 
the  members  of  any  other  order. 

Honey  Bee  (Apis  mellifica) 

Honey  bees  are  social  insects,  dwelling  in  colonies  com- 
posed of  three  kinds  of  individuals.  The  males  perform  no 
work  and  are  therefore  called  drones.  The  imperfectly 
developed  females  are  named  workers,  because  they  per- 
form all  the  labor.  The  perfect  females  of  which  only  one 
is  allowed  to  remain  in  a  hive  are  the  queens.  They  do 
nothing  but  lay  the  eggs.  A  colony  after  taking  possession 
of  a  hive  or  hollow  tree  forms  out  of  wax  secreted  by  the 


FIG.  32. — Photograph   of  honeybees    natural  size,      a,  drone;  b,  worker;  c, 
queen. 

workers  a  comb  of  many  hexagonal  cells.     During  the 
summer  many  of  these  cells  are  stored  with  honey  for  food 


HYMENOPTERA 


53 


FIG.  33.  —  An  egg,  four  larvae,  aad 
two  pupae  of  the  honey  bee  in 
their  cells.  Natural  size. 


in  winter.  This  is  not  found  in  flowers,  as  is  generally 
supposed,  but  is  manufactured 
by  the  bees  from  nectar 
produced  by  glands  in  the 
flower.  The  nectar  passes  into 
the  honey  stomach  where  cer- 
tain secretions  act  on  it  before 
it  is  regurgitated  into  the  cells 
of  the  comb. 

The  amount  of  work  accomplished  by  a  hive  of  bees 
is  wonderful.  A  single  swarm 
has  been  known  to  collect 
thirty-two  pounds  of  material 
in  a  day  and  some  swarms  of 
the  Cyprian  breed  have  pro- 
duced one  thousand  pounds  of 
honey  each  in  a  season.  The 
usual  yield  for  a  colony  is  less 
than  a  hundred  pounds  annually. 
Some  of  the  cells  are  used  for 
breeding  purposes.  The  queen 
seems  able  at  will  to  lay  eggs 
that  will  produce  either  drones 
or  females.  The  eggs  destined 
to  become  queens  are  laid  in 
larger  cells,  and  the  larvse,  foot- 
less white  grubs,  are  furnished  a 
specially  nutritious  diet. 

Honey  bees  are  valuable  not 
only  for  the  honey  and  wax  pro- 
duced, but  also  as  a  means  of  cross-fertilizing  flowers. 


FIG.  34.  —  Alimentary  canal  of  a 
honey  Dee.  st,  honey  stomach  ; 
s,  true  stomach  ;  nt,  intes- 
tine ;  o,  esophagus  ;  sg,  salivary 
glands  ;  fc,  kidneys.  Enlarged 
six  diameters. 


54 


ARTHROPODA 


FIG.  35.  —  Flower  with  one  petal  turned  down 
to  show  the  single  female  organ,  the  pistil, 
projecting  a  quarter  of  an  inch  above  the 
several  male  organs,  the  stamens. 


Usually  blossoms  con- 
tain within  the  showy 
colored  cup  a  central 
pinlike  filament,  the  fe- 
male organ,  or  pistil 
surrounded  by  several 
threadlike  filaments  with 
elongated  heads  giving 
off  a  fine  powder,  the 
male  elements  called  pol- 
len, which  by  coming  in 
contact  with  the  pistil 
causes  it  to  produce 
seeds  and  fruit.  Ex- 
periments have  shown 
that  when  the  bees  transfer  the  pollen  from  one  blossom 
to  another  more  fruit  and  of  much  finer  quality  results 
than  if  the  pistil  is  fertilized  by  the  pollen  of  the  same 
blossom. 

Bumble  Bee  (Bombus  fervidus) 

The  common  bumble  bee  belongs  to  a  group  of  social 
bees  dwelling  in  communities  of  rather  limited  numbers. 
Early  in  the  spring  the  queen,  the  only  one  of  the  colony 
living  through  the  winter,  constructs  waxen  ovoidal  cells 
in  an  abandoned  mouse's  nest  and  lays  eggs  hatching  into 
workers.  These  like  the  honey  bees  are  imperfect  females 
and  much  smaller  than  the  queen  who  no  longer  collects 
food  but  attends  to  home  duties  consisting  mostly  of  egg 
laying.  In  July  some  of  the  eggs  are  infertile  and  there- 


HYMENOFrERA 


55 


FIG.  36. — Photograph  of  bumble  bees,    a,  queen;  6,  worker;  c,  drone.    Natural 

size. 

fore  hatch  into  males  also  called  drones.  These  fertilize 
a  few  of  the  queens  hatching  late  and  at  the  beginning  of 
winter  die,  as  do  also  all  the  workers. 


Wasps 

Among  the  wasps  are  both  social  and  solitary  forms. 
The  common  bald-faced  hornet  (Vespa  maculata),  the 
yellow  jacket  (Vespa  germanica),  and  the  familiar  paper 

wasp  (Polistes)  all  have  a 
life  history  similar  to  the 
bumble  bee.  The  sand 
wasps  and  mud  wasps  are 
solitary  forms  of  much  the 
same  habits.  The  latter 
construct  mud  cells  side  by 
side  against  the  walls  or 


FIG.  37. —  Yellow  jacket.      Photograph, 
natural  size. 


ceilings  of  a  building  and 
after  depositing  an  egg  in 
each  cell  stored  with  several  paralyzed  spiders  or  other 
small  insects  seal  it.  The  mother  paralyzes  the  insects 


56  ARTHROPODA 

intended  for  food  for  her  young  by  stinging  them  in  a  chief 
nerve  center.  To  find  the  young  and  their  food  the  nests 
should  be  examined  in  May  or  June.  The  adult  mud  wasp 
may  be  recognized  by  the  threadlike  connection  between  the 
thorax  and  abdomen. 

Ants 

The  numerous  species  of  ants  are  distinguished  from 
the  other  members  of  the  order  by  one  or  two  swellings  on 
the  slender  stem  (petiole)  connecting  the  thorax  and  ab- 
domen. They  dwell  in  communities  in  which  there  may 
be  as  many  as  five  different  castes  or  forms.  In  addition 
to  the  ordinary  winged  males  and  females,  there  are  two 
kinds  of  workers,  and  the  soldiers  adapted  for  fighting. 


FIG.  38. — Photograph  of  ants,    a,  cocoon  containing  a  larva  ;  6,  larva  ;  c,  pupa  ; 
d,  adult  worker  ;  e,  queen.    About  natural  size. 

The  workers  as  with  the  bees  are  undeveloped  females 
which  never  possess  wings.  The  true  females  or  queens 
have  wings  in  the  early  part  of  the  year  until  after  the 
nuptial  flight,  at  the  end  of  which  they  tear  them  off  and 
seek  places  to  lay  their  eggs  beneath  stones,  in  decaying 
wood,  or  under  the  bark  of  trees. 


HYMENOFIERA 


57 


Ant  nests  are  easily  found  in  decaying  logs  and  under 
stones  and  boards  during  the  summer  and  autumn  months 
containing  eggs,  larvse,  pupse,  workers,  and  queens.  The 
eggs  are  white,  just  visible  to  the  naked  eye,  and  the  larvse 
may  be  distinguished  from  the  pupse  sometimes  encased  in 
cocoons,  by  the  ab- 
sence of  legs. 

The  favorite  food 
of  some  ants  is  the 
honey  dew  ex- 
creted by  plant  lice 
from  the  alimen- 
tary canal.  Most 
ants  are  fond  of 
any  kind  of  sweets 
and  sometimes 
cause  much  annoy- 

•  i  FIG.  39.— Wheat   plant   louse   enlarged 

ance  in  houses. 
They  are  easily  got 
rid  of  by  sprink- 
ling places  frequented  by  them  with  a  mixture  of  four 
parts  pulverized  sugar  and  one  part  arsenic.  More  than 
two  thousand  species  of  ants  have  been  described.  A 
half  dozen  different  species  may  be  found  in  almost  any 
locality. 

Sawflies 

The  sawflies  are  so  named  because  of  the  structure  of 
the  ovipositor  which  contains  two  saws  capable  of  being 
moved  up  and  down  to  make  apertures  in  vegetable  tissue 
to  receive  the  eggs.  The  habits  of  these  insects  which  are 


about   five 

times,  a,  winged  female;  d,  wingless  female  with 
a  hole  from  which  a  parasite  escaped;  b,  young  louse. 
After  Biley. 


58 


ARTHROPODA 


not  true  flies  are  easily 
learned  from  observing 
the  common  currant 
worm  ( Nematus  ri- 
besii).  The  minute 
elongate  eggs  are  de- 
posited on  the  under 
sides  of  the  currant 
leaves  and  gooseberry 
leaves  in  May  and  June 
where  they  hatch  into 
yellowish  green  cater- 
pillarlike  larvae  attaining  their  full  size  of  an  inch  in  about 
two  weeks.  They  then  drop  to  the  ground,  and  just  be- 


PlG.  40.  —  Photograph  of  currant  sawfly,  and  co- 
coon dug  from  the  ground.  Twice  natural  size. 


FIG.  41.  —  Photograph  of  a  leaf  of  currant  with  eggs  of  the  sawfly  in  their  charac 
teristic  location  along  the  veins.    Twice  natural  size. 

neath  the  surface  form  cocoons  from  particles  of  earth 
within  which  they  transform  to  pupae  and  a  few  days  later 


HYMENOPTERA 


59 


to  the  adult  form.  Of  the  two  generations  in  the  year, 
the  one  going  into  the  cocoon  state  later  remains  therein 
over  winter.  The  easiest  way  to  study  the  life  of  this  in- 
sect is  to  place  in  a  box  an  inch  layer  of  quite  moist  soil 
and  several  larva?,  which  must  be  fed  twice  daily  for  about 
a  week  until  they  disappear  in  the  dirt.  At  intervals  of 
three  days  different  cocoons  should  be  opened  to  note  the 
progress  of  the  transformation  from  the  larvse  to  the  adult 
state,  occupying  about  a  fortnight. 

The  sawflies  numbering  two  thousand  species  cause  an 
immense  amount  of 
damage.  One  kind 
defoliates  the  larch, 
another  the  elm,  while 
the  common  rose  slug, 
the  larva  of  a  small 
sawfly,  causes  havoc 
to  the  rose  bushes. 


FIG.  42. —Photograph   of   the  currant  worm. 
Natural  size. 


The  slimy  dark-olive 

pear  slug,  common  on 

the  under  side  of  the 

pear,  cherry,  and  plum  leaves  in  early  summer,  winters 

in  a  cocoon  under  ground  and  transforms  to  a  sawfly  the 

following  spring.    All  the  larva?  are  easily  destroyed  by 

dusting  the  plants  with  hellebore. 

Gallflies 

The  gallflies,  more  properly  called  wasps,  as  they  have 
four  wings,  are  minute  insects  about  a  quarter  inch  long 
with  many-jointed  antennae  and  a  chunky  abdomen. 
They  derive  their  name  from  the  fact  that  most  of  the 


60 


ARTHROPODA 


fifteen  hundred  species  lay  their  eggs  in 
some  part  of  a  plant,  and  the  develop- 
ing   larvaB  by  their    excretions    cause 
an  overgrowth  of  tissue  producing  an 
enlargement  called  a  gall.      The  oaks 
are   most    frequently  affected.      Each 
species    forms    its    characteristic    gall 
FIG.  43.  —  Photograph      and  always  on  the  same  kind  of  plant, 
of  oak  gaiifly  en-      ^  g^i  opened  hi  May  or  June   will 

larged  twice.  .  ..,.", 

usually  contain  a  single  wormlike  white 
larva.  The  flies  may  be  secured  from  many  of  the  galls 
by  tying  a  piece  of  cheesecloth  over  them  in  early  June 


FIG.  44. —  On  the  left  three  galls  or  oak  apples,  of  which  two  are  cut  open,    a, 
larva.     On  the  right  an  oak  gall  about  one  month  old.     Photograph  by  Overton. 

or   by  merely  collecting  them  about  the  middle  of  June 
and  placing  in  a  tight  box  until  the  flies  appear.     Some- 


HYMENOPTERA 


61 


times,  instead  of  the  expected  gall  insects,  a  number  of  very 
minute  Chalcis  flies  appear.  These  in  their  larval  stage 
are  parasites  on  the  gallflies  (Fig.  59). 

Galls  used  in  the  making  of  ink  and  tannic  acid  are  pro- 
duced by  a  species  of  Cynips  on  the  oaks  of  Asia  and 
Europe.  A  few  of  the  Diptera,  many  of  the  Hemiptera, 
and  some  of  the  Arachnida  also  produce  galls.  The  maple 
spot  gall,  so  common  on  the  leaves  of  the  red  maple,  is 
made  by  the  fungus-gnat  (Sciara)  of  the  order  Diptera.  The 
conical  gall  of  the  witch-hazel  is  produced  by  a  plant  louse, 
as  is  also  the  cockscomb  gall  on  the  elm  leaves. 


FIG.  45.  —  Blackberry  knot 
gall  common  on  the  stems 
of  the  blackberry.  Nat- 
ural size. 


FIG.  46.— Maple  spot  gall  produced  by 
a  fly. 


Fig  Producers.  — The  fig  insect  (Blastophaga  grossorwn) 
is  the  most  valuable  member  of  the  gall  family,  as  with- 


ARTHROPODA 


out  its  presence  it  is  impossible  to  produce  a  first-class  fig 
at  a  reasonable  price.  Only  since  the  year  1900  has  the 
secret  of  growing  high-grade  figs  been  utilized  in  this  coun- 
try. The  Smyrna  fig  cultivated  hi  California  bears  only 


a  b  £  d 

FIG.  47. — Figs,  a,  and  dt  unfertilized ;  6  and  c,  fertilized.    After  Howard. 

female  flowers  within  the  hollow  globular  receptacle  form- 
ing the  flesh  of  the  fig.    The  fig  will  lack  the  desired  flavor, 

sweetness,  and  size  un-       

less  it  is  fertilized,  i.e., 
unless  pollen  from  male 
fig  flowers  is  carried 
through  the  minute 
orifice  at  the  point  op- 
posite the  stem  and 
distributed  over  the  fe- 
male flowers,  causing 
them  to  produce  seeds. 
The  wild  figs  have  both 
lands  of  flowers,  and 
when  these  are  planted 
near  the  Smyrna  fig 

trees  the  fig  insects  emerging  from  the  galls  surrounded  by 
male   flowers  carry  with  them  some  pollen  on  the  wings 


FlG.  48.  —  Photograph  of  the  cut  surface 
of  a  wild  fig  showing  over  twenty  galls  : 
a,  place  where  the  insect  enters  the 
young  fig  to  lay  eggs. 


HYMENOPTERA 


63 


and  legs  as  they  pass  out.  At  once  they  enter  another 
fig  to  deposit  eggs.  If  this  is  a  Smyrna  fig,  its  female 
flowers  will  be  dusted  with  pollen  from  the  insect  and 


FIG.  49  —Fig  insects;    a,  female;  e,  emerging  from  a  gall,  many  of  which  are 
seen  in  Fig.  48.     Lines  at  right  show  natural  size.    After  Howard. 

thereby  fertilized.  The  insect  will  not  lay  eggs  in  the 
Smyrna  fig,  but  only  in  the  wild  fig;  therefore  one  indi- 
vidual may  carry  the  pollen  to  a  dozen  Smyrna  figs  be- 
fore finding  a  wild  fig  whose  character  it  does  not  recog- 
nize before  entering  within  the  receptacle. 

Ichneumon  Flies 

The  ichneumons  are  incorrectly  called  flies,  as  they  have 
four  wings.  They  go  a  step  further  in  parasitism  than  the 
preceding  group,  as  they  are  parasitic  on  or  within  other 
insects  and  usually  while  the  latter  are  in  the  larval  or 
pupal  stage.  There  are  over  five  thousand  species  vary- 
ing in  size  from  an  eighth  of  an  inch  to  one  and  a  half 


64 


ARTHROPODA 


inches  in  length.  They  may  be  recognized  by  the  division 
of  the  under  side  of  the  last  segment  of  the  abdomen,  the 
attachment  of  the  ovipositor  before  the  tip  of  the  abdo- 
men, and  usually  the  heavy  marginal  vein  of  the  front 

wings  with  a  dark 
spot  near  its 
middle.  Pimpla 
inquisitor  is  a 
widespread  para- 
site of  the  tent 
caterpillar,  army 
worm,  tussock 
moth,  and  fall 
web  worm.  It  de- 
posits from  five 
to  ten  eggs  be- 
neath the  skin  of 
its  victim,  within 
which  the  larvsa  feed  a  few  days  until  they  attain  adult 
size.  They  then  emerge  and  spin  their  cocoons  in  a 
bunch  wherein  transformation  to  the  adult  occurs. 

In  the  autumn  of  1901  fall  webworms  were  so  numer- 
ous in  Eastern  Pennsylvania  that  scarcely  a  tree  was  to  be 
found  that  did  not  harbor  from  a  dozen  to  a  hundred. 
They  crawled  over  the  sidewalks  and  crept  up  the  houses. 
In  late  autumn  they  formed  cocoons  of  which  I  collected 
a  large  number,  and  in  over  ninety  per  cent  of  them  the 
insect  had  been  devoured  by  the  larvae  of  the  Pimpla.  As 
a  result,  the  webworms  instead  of  being  numerous  the 
following  season  were  very  few. 
A  small  ichneumon  often  attacks  the  large  green  tomato 


FIG.  50.  — Pimpla  inquisitor,  an  ichneumon,  enlarged 
about  three  times. 


FIG.  51.  —Bunch  of  Pimpla  cocoons  removed  from  the  cocoon  of  the  fall  webworm, 
and  the  larval  parasite. 


FIG.  52.— Photograph  of  ichneumon  larvae  issuing  from  the  Catalpa  caterpillar. 
Natural  size. 


FlG.  53.— Photograph  three  hours  later  of  the  same  caterpillar  as  shown  in 
Fig.  52.    Slightly  enlarged.  (65) 


66 


ARTHROPODA 


PIG.  54.— One  of  the  many  adult 
insects  that  came  from  the  cocoons 
shown  in  Fig.  53.  Enlarged  six  times. 


FIG.  55.  — Photograph  of  Ophion.    Nat- 
ural size. 


worm  upon  which  its  cocoons  may  be  seen  in  late  summer 
or  autumn.  A  simi- 
lar species  is  para- 
sitic in  the  larva  of 
the  hawk  moth  feed- 
ing on  the  leaves  of 
the  Catalpa  tree  in 
September.  Ophion 
and  Trogon  are  two 
of  the  large  forms 
often  issuing  from 
the  cocoons  of  the 
swallowtail  butter- 
flies. Thalessa  is 
distinguished  by  its 
long  ovipositor  used 
in  depositing  eggs  an  inch  or  two  within  a  tree  where 


FIG.  56.  — Photograph  of  Thalessa;  ot  the  ovi- 
positor equal  in  length  with  the  two  supports 
was  inserted  two  inches  in  an  ash  tree,  and  was 
broken  in  the  attempt  to  remove  it. 


HYMENOFrERA 


67 


FJG.  57.  —  Thalessa  boring  in  an  ash  tree  to 
deposit  its  eggs  in  the  burrow  of  a  horn-tail 
larva,  a  wood  borer.  Photograph,  nat- 
ural size. 


the  larvae  may  feed  on 
wood-boring  larvae.  .  Ich- 
neumon flies  render  great 
service  to  agriculture  by 
keeping  in  check  the 
harmful  caterpillars. 

Chalcis  Flies 

The  chalcids  have 
habits  similar  to  the  ich- 
neumons from  which  they 
may  be  distinguished  by 
the  outward  bend  of  the 
antennae  and  the  almost 
entire  absence  of  veins 

in  the  fore  wings.  They  are  all  small,  being  from  an  eighth 
of  an  inch  to  a  fourth  of  an  inch  long.  Large  numbers  of 

them  may  be  se- 
cured by  collecting 
a  dozen  or  two 
cabbage  worms 
(Fig.  67)  in  au- 
tumn and  feeding 
them  daily  with 
fresh  cabbage 

FIG.  58.  — A  bunch  of  five  chalcid  larvae  on  the  canker       i  WitViin 

worm.    Photograph,  twice  natural  size.  leaves. 

a    week     chalcid 

larvae  will  be  seen  to  issue  from  several  and  spin  cocoons 
immediately  in  which  they  may  remain  all  winter  or  if  early 
in  the  season  transform  to  pupae  and  adults  in  about  two 
weeks.  Three  out  of  every  ten  oak  galls  in  late  summer 


ARTHROPODA 


contain  Chalcis  larvae  which  have  devoured   the  gallfly 
larva.     Some  chalcids  lay  their  eggs  on  the  skin  of  the 
host  as  in  the  case  of  Euplec- 
trus    (Fig.    58),    while    others 
insert  the  eggs  within  the  tis- 
•k  sues    and    the    larva?   do  not 

Jfc  AK          appear   on    the    surface    until 

^11  •         they  are  ready  to   spin  their 

cocoons. 
That    the  chalcids  are  most 


FlG.  59.  —  Chalcids  transformed 
from  the  larvae  shown  in  Fig.  58. 
Photographed  nine  days  after  Fig. 
58.  Enlarged  eight  times. 


effective  helps  to  man  may  be 
seen  from  the  fact  that  in  one 
year  in  the  cotton  fields  of 
Florida  ninety-five  per  cent  of 

the  eggs  from  which  would  have  hatched  the  destructive 
cotton  caterpillar  were  killed  by  a  species  of  Chalcis. 

4.   LEPIDOPTERA 

This  order  includes  the  butterflies  and  moths,  which  are 
readily  distinguished  from  other  insects  by  the  presence 
of  two  pairs  of  wings  covered  with  scales.  In  a  few  species 
the  female  has  no  wings.  Butterflies  usually  fly  by  day 
and  moths  by  night.  When  resting  the  wings  of  a  butter- 
fly are  held  vertical  over  its  back,  but  a  moth  at  rest 
holds  its  wings  expanded  or  lying  flat  on  its  back.  The 
antennae  of  a  butterfly  are  clubbed  or  enlarged  at  the 
end,  while  those  of  a  moth  taper  and  are  often  feathered 
throughout.  The  larvae  of  butterflies  never  construct  co- 
coons, while  those  of  most  moths  spin  or  weave  cocoons 
for  the  pupal  stage. 


LEPIDOPTERA 


Butterflies 

The  seven  hundred  species  of  butterflies  in  North  Amer- 
ica, distributed  from  Central  America  to  the  Arctic  Circle, 
are  chiefly  of  value  to  man  through  the  pleasure  and  profit 
they  afford  lovers  of  nature.  Two  or  three  species  are  de- 
cidedly harmful  hi  the  larval  form.  The  two  groups  most 
abundantly  represented  in  the  temperate  zone  are  the 
brush-footed  tribe  and  the  swallowtails. 

Brush-footed  Butterflies.  —  This  group,  whose  members 
have  imperfect  fore  legs,  includes  a  number  of  common 


FIG.  60.  — Photograph  of  two  larvae  and  two  adults  of  the  Monarch  butterfly. 
One  third  natural  size. 

large  forms.  The  milkweed  butterfly  or  monarch  (Anosia  plex- 
ippus)  is  quite  as  conspicuous  as  its  black,  white,  and  yel- 
low-banded larva  and  bright  green  gold-spotted  chrysalis 


ARTHROPODA 


FIG.  61.  —  Silver-spotted  fritillary.    Photograph,  natural  size. 


FIG.  62. — The  mourning  cloak.    Photograph,  natural  size. 


LEPIDOPTERA 


71 


found  on  the  milkweed  from  June  till  September.  The 
Silver-spotted  fritillary  (Argynis),  whose  larva  feeds  on 
violets,  and  the  mourning  cloak  (Vanessa  antiopa),  whose 
larva  feeds  on  willows  and  poplars,  are  easily  secured  for 
study.  The  mourning  cloak  is  the  only  kind  of  butterfly 
frequently  seen  in  February  and  March. 

Swallowtails.  —  The  swallowtails  and  their  allies  making 


FIG.  63 — Common  swallowtail,  Papilio  asterias ;  A,  larva;  £,  preparing  to 
enter  on  the  pupal  state  ;  C,  pupa  as  photographed  twenty-four  hours  after. 

up  the  family  Papilionidae  have  six  perfect  feet,  and  most 
of  the  swallowtails  are  characterized  by  a  projection  at  the 

posterior  angle  of 
each  hind  wing. 
They  pass  the  win- 
ter in  the  chrysalid 
or  pupal  state,  be- 
ing always  fastened 
by  a  girdle  near 
the  middle.  The 
larvae  are  naked 
caterpillars,  usu- 
ally of  a  green 
color,  and  feed  upon  a  variety  of  plants.  A  most  widely 
distributed  form  is  the  cabbage  butterfly  (Pieris  rapce), 


FIG.  64.  —  Photograph  of  the  common  swallowtail, 
Papilio  asterias.    One  half  natural  size. 


72 


ARTHROPODA 


FIG.  65. —Photograph  of  the 
larva  of  a  tiger  swallowtail. 
Natural  size. 


whose  life  history  may  be  studied 
to  the  best  advantage  in  late 
summer  and  autumn.  The  spe- 
cies was  brought  from  England 
to  Quebec  about  1860  in  im- 
ported cabbages.  In  three  years 
it  had  spread  over  an  area  of 
sixty  miles  in  diameter.  By 
1871  it  was  present  throughout 
eastern  Canada  and  New  Eng- 
land. Ten  years  later  it  was 
common  from  Hudson  Bay  to 
Texas,  and  since  1895  it  has 
been  a  pest  from  the  Pacific  to 
the  Atlantic. 
The  green  larvse  are  found  from  June  to  November  by 

noting  on  the  cab- 
bage    plants     the 

dark    shotlike   ex- 
cretions indicating 

the  presence  of  the 

animals.      Several 

placed    in    a    box 

and  fed  daily  with 

fresh      cabbage 

leaves   will  within 

a  week  or  two  form 

cases    of    the  last 

molted    skins  and 

change  to  the  pupal 

state,  lasting  in  early  summer  but  a  few  days,  while  later 


FIG.  66.  — Photograph  of  pupal  or  chrysalitl  case  and 
the  black  swallowtail  that  came  from  it.  Two 
thirds  natural  size. 


LEPIDOPTERA 


73 


it  may  continue 
through  the  winter. 
Some  of  the  larvae 
collected  will  be 
found  to  be  infested 
with  chalcid  para- 
sites which  issuing 
through  the  skin  of 
the  host  will  spin 
numerous  small  oval 
cocoons  thereon.  A 
larva  thus  affected 
dies. 

Moths 


The  Species  Of  the      FIG.  6?.—  Photograph    of   cabbage    butterfly   and 

moths     are     more  larva>  the  latter  enlar8ed  twice- 

numerous  than  the 

butterflies,  and  some  of  them  are  great  pests  in  the  larval 
form,  though  harmless  in  the  imago  (adult)  state.  A 
brief  description  of  one  or  more  species  of  the  nine  most 
important  groups  will  give  a  clear  idea  of  the  relation  of 
these  insects  to  man. 

Hawk  Moths  (Sphingidae). — The  sphinxes  are  the 
narrow-winged  moths  that  visit  the  flowers  at  dusk  and  by 
some  are  supposed  to  be  humming  birds.  The  tongue  is 
in  some  species  four  or  five  inches  long,  but  is  kept  closely 
coiled  except  when  probing  the  flowers  for  nectar.  The 
larva  is  characterized  by  a  horn  on  the  top  of  the  last  seg- 
ment, or  in  its  place  a  glossy  eye  spot,  giving  it  a  formidable 


AETHROPODA 


appearance  though  it  is  entirely  harmless.     It  enters  the 
ground  to  pupate  without  spinning  a  cocoon.    The  cater- 


PlG.  68.  —  Photograph  of  the  tomato- worm  moth  with  its  tongue  uncoiled. 
One  half  natural  size. 

pillar  defoliating  the  Catalpa  trees  in  September,  the  large 
green  tomato  worm,  and  the  tobacco  worm  often  injuring 
the  tobacco  crop, 
are  larva?  of  sphinx 
moths. 

Spinners  (Bom- 
bycidae).  —  This 
group  is  so  named 
because  the  larva? 
spin  cocoons  in 
which  to  pupate. 
They  are  distin- 

,  FIG.  69.  —  Photograph  of  tomato  worm,  the  larva  of 

the         the  moth  shown  in  Fig.  68.    Two  thirds  natural  size. 


LEPIDOPTERA 


76 


hawk  moths  by  their  hairy  bodies,   and  pectinated  or 
feathered  antennae.    The  larvae  of  the  large  forms  are 


FIG.  70.  —  Photograph  of  the  larva,  pupa,  and  imago  of  the  Catalpa  sphinx  (Cera- 
tomia).    Natural  size. 

called    giant    silkworms.     Polyphemus  is   the   American 

silkworm. 
The  silk  of  commerce  is  produced  by  the  domesticated 

silkworm  of  China  (Sericaria  mori).     In  parts   of   China 

the  moths  live  in  a  wild  state,  but  in  several  portions  of  the 

Old  World  the  in- 
sect has  been  domes- 
ticated. The  entire 
life  history  of  the 
moth  may  be  ob- 
served by  any  school 
able  to  secure  mul- 
berry 


FIG.  71.  —  Photograph  of  a  larva  of  polyphemus 
(.Teleapolyphemus).    Two  thirds  natural  size. 

or    osage 

orange  leaves.     If  neither  of  these  trees   grows    in   the 
locality,  two  or  three  white  mulberry  trees  should  be  set 


76 


ARTHROPODA 


FIG.  72.  — Photograph    of  Polyphemus.    Oue  half 
natural  size. 


out  or  seeds  planted.    The  eggs  of  the  silkworm  moth 

may  be  procured  of  T.  Keleher,  662  Massachusetts  Ave. 

N.  E.,  Washington, 
D.C.;  Dr.  W.  H. 
Hill,  Peoria,  111.; 
and  Mrs.  Carrie 
Williams,  1245  Lo- 
gan Ave.,  San  Di- 
ego, Cal.  If  kept 
cool  they  will  not 
hatch  until  late  in 
summer,  but  they 

may  be  made  to  hatch  during  April  or  May  by  placing 

them  in  a  warm  room  a  week.     As  soon  as  the  minute 

hairy    black     larvae 

break  from  the  eggs 

they  should  be  given 

very    small     tender 

leaves    or    larger 

leaves  cut  into  small 

pieces.  If  fed  sev- 
eral times  daily  with 

mulberry    or    osage 

orange  leaves  for  a 

month,  the  larva  will 

spin  a  cocoon  with 

the  secretion  of  the 

silk  glands   opening 

just      beneath     the 

mouth.  The  spin- 
ning occupies  three  days  or  more,  and  soon  after  its  com- 


FIG.  73.  —  Photograph  of  cocoons  of  promethea 
moth. 


LEPIDOPTERA  77 

pletion  the  larva  changes  to  a  pupa  which  in  a  -week  or 
two  is  transformed  to  a  white  moth  living  only  a  few  days 


FIG.  74.  — Chinese  silk  worm  spinning  its  cocoon  of  silk.    Photograph,  two  thirds 
natural  size. 


FIG.  75.  — Four  stages  of  the  Chinese  silk  worm.    The  moth  has  emerged  from  the 
cocoon  and  laid  some  eggs  on  it.    Photograph,  natural  size. 

after  emerging  from  its  silken  house.  If  the  cocoons  are 
wanted  for  silk,  a  day  or  two  after  their  completion  they 
are  baked  or  steamed  to  kill  the  pupa.  The  thread  form- 


78 


ARTHROPODA 


ing  the  cocoon  is  then  wound  off  on  a  reel,  and  is  often 
found  to  be  more  than  a  mile  long.  Three  thousand 
cocoons  are  required  to  make  a  pound  of  raw  silk,  and 
about  ninety  of  the  cocoon  fibers  as  spun  by  the  worm  are 
twisted  together  to  make  a  thread  of  sewing  silk. 

The  value  of  the  silkworm  was  dis- 
covered 1700  B.C.  by  the  wife  of  the 
third  emperor  of  China,  who  is  known 
as  the  goddess  of  silkworms.  For 
nearly  two  thousand  years,  the  Chinese 
kept  the  method  of  obtaining  silk  a 
profound  secret.  The  penalty  for 
carrying  the  eggs  out  of  China  was 
death.  In  555  A.D.,  two  Nestorian 
monks  were  bribed  by  the  Byzantine 
•emperor  Justinian  to  bring  him  silk- 
worm eggs  concealed  in  the  hollow  of 
their  pilgrim  staves.  The  industry  then 
spread  rapidly  throughout  Europe, 
and  in  1622  reached  America,  but 
owing  to  the  high  price  of  labor,  the 

na.  76. -snk  glands  of   insect  is  not   cultivated  here  to  any 
the  silk  worm.  Natural  great  extent.    From  twenty-five  thou- 
sand  to   fifty  thousand    cocoons    are 
required  to  produce  sufficient  silk  for  a  dress. 

The  forest  tent  caterpillar  (Clisiocampa  disstria)  and 
its  cousin,  the  apple  tree  tent  caterpillar,  are  the  only  larvae 
which  spin  webs  in  the  trees  hi  the  spring.  The  larvae 
break  from  the  egg  mass  surrounding  a  twig,  in  early  May, 
and  in  a  few  days  construct  a  tent  to  protect  themselves 
during  the  cold  rainy  weather.  They  grow  to  full  size  in 


LEPIDOPTERA 


79 


about  a  month,  when  they  crawl  to  secluded  places  and  spin 
yellow  cocoons  from  which  the  moths  emerge  two  weeks 
later  and  deposit  four  or  five  hundred  eggs  for  the  follow- 
ing season.  The  Baltimore  oriole  is  their  greatest  enemy. 
The  fallwebworm  (Hyphantria  textor)is  the  larva  spinning 
dense  webs  in  the 
trees  from  July  to 
September.  It 
passes  the  winter  as 
a  pupa  in  its  hairy 
cocoon  attached  to 
a  limb  or  a  leaf. 
The  white  moth 
comes  forth  the 
following  summer. 
If  these  pests  are 
numerous  one  year 
they  are  quite  sure 
to  be  scarce  the 
next,  as  the  ichneu- 
mon flies  prey  on 
them  extensively; 
otherwise  they 

WOUld        ruin        tne       Fm   77._Tnree  tents  of  tne  tent  caterpillar  in  a 
autumn    foliage    Of  tree  which  it  has  entirely  stripped  of  leaves. 

.  the  trees. 

Tussock  moths  of  several  kinds  consume  the  leaves  of 
the  shade  trees,  but  the  "  white-spotted  "  one  (Notolophus 
leucostigma)  is  the  commonest.  The  hairy  tufted  red- 
headed larvaB  are  found  on  the  trees  in  June  and  July,  and 
also  in  September  and  October.  There  are  two  generations, 


80 


ARTIIROPODA 


FIG.  78. —Photograph  of  tent  caterpillars  four  days  old  on  their  tent. 
Natural  size. 


the  first  of  which  hatches  from  the  white  frothy  eggs  de- 
posited by  the  wingless  female  in  late  autumn  and  remaining 
over  winter  on  the  trees.  The  eggs  for  the  second  genera- 
tion are  laid  in  late  summer.  In  July  and  September,  the 
light  yellowish  cocoons  an  inch  or  more  long  are  conspicu- 
ous objects  on  the  rough  bark  of  the  trees. 

The  gypsy  moth  (Ocneria  dispar),  occurring  only  in  Massa- 
chusetts and  Rhode  Island,  was  accidentally  introduced 
from  France  in  1868.  The  larva,  a  brownish  hairy  cater- 


LEPIDOPTERA 


81 


FIG.  79.  —  Photograph  of  mature  forest  tent-caterpillars  on  their  tent.    One 
third  natural  size. 


pillar  about  an  inch  and  a  half  long,  feeds  upon  many  kinds 
of  trees  and  plants.  Had  prompt  measures  been  used  in 
the  early  seventies,  the  plague  might  have  been  exter- 
minated, but  owing  to  ignorance  on  the  part  of  the  legisla- 
tors, no  organized  fight  was  made  against  the  devastator 
until  1890.  For  holding  in  check  this  pest,  the  Massa- 
chusetts legislature  appropriated  in  1893  one  hundred 


82 


AKTHROPODA 


FlG.  80.  —Eggs  and  moth  of  the  tent  caterpillar.    Twice  natural  size. 

thousand  dollars,  in  1894  the  same  amount,  and  the  follow^- 
ing  year  one  hundred  and  fifty  thousand  dollars.  Large 
appropriations  have 
been  made  later,  but 
the  enemy  still  con- 
tinues its  ravages, 
and  should  it  be 
carried  to  the  other 
states  a  national 
calamity  would  re- 
sult. 

Owlet  Moths  (Noc- 
tuidae).  —  These  are 
usually  of  a  somber 
gray  or  brown  color 

flnrl  VmVP  fl  wino-  P-X"-      FlG-  81'~ pllotograph  of  fal1  webworm  and  its  co- 
coon.   Nearly  twice  natural  size. 

pansion  of  from  one 

to  three  inches.      The  larvae  of  many  of  the  species  are 

known   as    cutworms,  because   in    the   spring  and   early 


LEPIDOPTEBA 


FIG.  82.  —Photograph  of  pupa  and 
moth  of  the  fall  webwonn.  Nat- 
ural size. 

summer  they  gnaw  off 
the  corn,  cabbage,  cot- 
ton, and  other  tender 
plants  near  the  surface 
of  the  earth.  Some  spe- 
cies climb  the  trees  and 
cut  off  the  tender  buds. 
Both  larvae  and  adults  are  usually  active  at  night  only. 
The  pupal  stage  is  passed  in  the  earth.  In  early  spring  the 
common  gray  cutworm  may  be  found  coiled  up  under 


FIG.  83. — Female  tussock  moth  which  has 
just  emerged  from  the  cocoon  at  the  left 
upon  which  it  has  deposited  over  two  hun- 
dred eggs.  Photograph,  slightly  enlarged. 


ElQ.  84.  —  Larva  of  tussock  moth.    Photograph  natural  size. 


84 


ARTHROPODA 


stones  and  boards,  while  later  it  and  allied  species  may  be 
found  by  digging  about  the  base  of  any  plant  which  has 

lately  been  cut  off  near 
the  surface  of  the  earth 
Winter  is  passed  in 
the  larval  state,  and 

FIG.  85.  —  Common  cutworm  (Agrotis),     Nat-      pupation     OCCUrS    in    the 
ural  size.  , 

ground. 

The  cotton-boll  worm  or  corn  worm  ( Heliothis  armiger)  in 
1902  damaged  the  cotton  crop  in  Texas  alone  to  the  extent 


FIG.  87.  —  Army  worm, 
natural  size. 


FIG.  86.  —  Cotton-boll  worm  or  corn  worm.     Two  larvaj, 
pupa,  and  adult.    After  Chittenden. 

of  four  millions  of  dollars,  and  in  1893  to  the  extent  of  five 
millions  of  dollars.  It  also  attacks  other  plants,  especially 
the  ears  of  sweet  corn.  The  army  worm  (Leucania  uni- 


LEPIDOPTERA 


85 


r'lG.  88. — Photograph  of  the  eggs,  larva,  and  moths,  male  and  female,  ol  the  fall 
canker  worm.    Enlarged  slightly. 

puncta)  often  travels  in  armies  composed  of  millions  of 
individuals  which  destroy  acres  of  vegetation  in  a  single 
day.  The  adult  is  a  gray  moth. 

Measurers  (Geometridae). — The  larvae  of  these  moths 
are  called  measuring  worms,  and  may  be  distinguished  by 
their  characteristic  walk,  which  consists  of  attaching  the 
three  front  legs  and  then  elevating  the  middle  portion  of 


86  ARTHROPODA 

the  body  to  form  a  loop  as  the  hind  legs  are  brought  for- 
ward. Of  the  many  species  the  most  injurious  ones  are 
the  canker  worms.  There  are  two  kinds.  The  fall  canker 
worm  (Anisopteryx  pomclaria)  ruins  the  leaves  of  the 
orchards  in  certain  localities  in  the  northern  parts  of  our 
country  during  the  month  of  June.  The  pupal  state  is 
passed  in  the  earth  within  a  dense  yellow  silken  cocoon, 


FIG.  89.  —  Photograph  of  a  colony  of  oak-leaf  rollers.    One  sixth  natural  size. 

from  which  the  moth  comes  forth  in  late  autumn  to  deposit 
three  or  four  hundred  eggs  on  the  limb  of  a  tree.  The 
female  moth  is  wingless,  and  therefore  the  pest  spreads 
over  new  territory  slowly'.  The'  spring  canker  worm, 
similar  to  the  fall  species,  is  common  in  the  Mississippi 
valley  and  throughout  the  West. 

Leaf  Rollers  (Tortricidae). — These  constitute  a  family 
of  rather  small  moths  whose  larvae  often  roll  up  the  edges 
of  the  leaves  and  line  the  interior  with  silk  to  form  a  cocoon. 
Some  species,  such  as  the  oak-leaf  roller  (Caccecia  fervidana), 


LEPIDOPTERA 


87 


live  in  colonies  forming  webs  in  midsummer,  within  which 

they  pupate. 
The  coddling  moth  (Carpocapsa  pomonelki)   is  familiar 

to  most  pupils  in  its  larval 

form  as  the  whitish  worm 

found  in    apples,    pears, 

and    quinces.     About   a 

Week  after  the  trees  bloom 

the  brownish-gray  moth 

emerges    from  its  silken 

cocoon   beneath   a  loose 

piece  of  bark  and  lays  a 

minute  white  egg  on  each 

of  fifty  or  more  leaves  and 

apples.     In  less  than  two 

weeks    the    larva  enters 

the  fruit  at  the  blossom 

end  and  eats  out  a  large  cavity,  causing  it  to  fall  to  the 
ground.  Soon  after,  the  worm  finds  a 
secluded  spot,  constructs  a  cocoon  in 
which  it  remains  a  fortnight  before 
transformation  to  the  adult  moth  is  com- 
pleted. In  regions  north  of  the  latitude 
of  Buffalo  the  larva  remains  in  its 
cocoon  over  winter,  but  farther  south 
there  are  usually  two  generations  and 
the  larva  of  late  summer  only  remains 
over  winter.  The  pupa  and  adult  are 

easily  obtained  by  removing  a  large  larva  from  an  apple 

in  June  and  feeding  it  daily  in  a  covered  jar  with  fresh 

apple  until  it  spins  a  cocoon. 


FIG.  90.  —  Photograph  of  half  an  apple  con- 
taining the  larva  of  the  coddling  moth. 
Nearly  twice  natural  size. 


FIG.  91.  — Coddling 
moth.  Photograph, 
slightly  enlarged. 


88 


AKTHROPODA 


FlG.  92. —  Larva  of  clothes  moth(  Tinea  pellionella) 
half  out  of  its  case.  Photograph,  three  times  nat- 
ural size. 


The  damage  this  pest  causes  annually  in  Illinois  has 
been  estimated  at  $2,375,000,  in  Nebraska  $2,000,000,  and 
in  New  York  $3,000,000.  Not  a  state  in  the  Union  is 
exempt  from  its  ravages,  which  are  somewhat  limited  by 
the  woodpeckers,  and  may  be  almost  entirely  avoided 

by  spraying  the 
trees  in  accord- 
ance with  direc- 
tions furnished 
by  the  United 
States  Depart- 
ment of  Agricul- 
ture. 

Tiny  Moths  (Tineidae). — These  are  small  moths  with 
pointed  and  fringed  wings.  Most  important  among  them 
are  the  clothes  moths,  of  which  there  are  two  common 
species. 

The  southern  clothes  moth  (Tineola  biselliella)  is  of  a 
pale-yellowish  color  without  spots.  Its  larva,  a  hairless 
white  worm  a  half  inch  long,  feeds  upon  museum  speci- 
mens, furs,  feathers, 
and  hair.  The  ordi- 
nary clothes  moth 
(Tinea  pellionella) 
may  be  distinguished 
from  the  above  species 

i  .-,          -i  -ii       FIG.  93. — Empty  pupa  case  of  the  clothes  moth. 

by    the    less    pointed 

wings  and  the  presence  of  a  few  dark  spots  on  the  anterior 
wings.  The  white  naked  larva  weaves  a  cocoon  which  is 
carried  about  and  enlarged  to  meet  the  growing  demands 
of  the  inmate.  Finally  within  this  cocoon  the  larva  trans- 


LEPIDOPTERA 


forms  to  the  pupa,  lasting  about  three  weeks.  The  moths 
emerge  from  May  to  August,  take  no  food,  and  after  de- 
positing their  eggs  on  any  woolen  material,  soon  die.  The 
larvae  feed  upon  all  sorts  of  woolen  goods.  In  winter  they 
may  be  often  found  in  their  woven  cases  adhering  by  their 
ends  to  the  lids  of  boxes  or  the  ceilings  of  rooms. 


FIG.  94.  —  Clothes  moth  (Tinea 
pellionella).  Photograph, 
twice  natural  size. 


FIG.     95.  —  Moth    of    the 
maple     borer.      Natural 


Clear- winged  Moths  (Sesiidae). — These  are  wasplike 
moths  of  brilliant  colors  and  have  transparent  wings.  They 
generally  fly  by  day.  Their  larvse  live  in  the  stems  of 
herbs  and  shrubs  or  the  trunks  of  trees.  Usually  each 
species  confines  its  depredations  to  a  certain  kind  of  plant 
or  tree.  The  empty  pupa  cases  of  the  maple  borer  (Sesia 
acerni)  may  be  seen  protruding  from  round  holes  in  the 
soft  maples  during  the  month  of  June.  The  squash  borer 
may  often  be  found  during  early  summer  in  dead  and  dying 
squash,  pumpkin,  melon,  and  cucumber  vines,  just  be- 
neath or  at  the  surface  of  the  ground.  It  is  a  widespread 
pest. 

The  moth  of  the  peach  tree  borer  (Sanina  exitiosa)  de- 
posits during  May,  June,  or  July  one  or  more  yellowish 


90 


ARTHROPOD A 


almost  invisible  eggs  on  the  bark  of  stone-fruit  trees  near 
the  ground.  The  white  larva  bores  into  the  tree,  feeding 
on  the  sap  wood  near  or  below  the  surface  of  the  ground, 
and  making  its  presence  known  by  the  exudation  of  gum 
and  fragments  of  borings  about  the  base  of  the  tree.  By 
late  autumn  it  is  almost  an  inch  long,  and  it  then  remains 
dormant  until  the  following  spring.  The  approach  of 
warm  weather  again  stimulates  it  to  feed  a  few  weeks  and 


FIG.  96.  —  Peach,  tree  borer  ;  a,  female  moth  ;  6,  male  moth  ;  d  and  e,  pupae  ;  c,  lar- 
,  va  ;/,  chip  cocoon  with  extruded  pupa  skin.  Natural  size,  after  Marlatt. 

in  late  spring  or  early  summer  its  transformation  to  pupa 
and  adult  is  accomplished  witliin  a  chip  and  gum  cocoon 
at  the  base  of  the  tree. 

Metamorphosis  among  the  Lepidoptera  is  complete,  i.e., 
there  are  four  well-marked  stages,  the  egg,  larva,  pupa,  and 
imago  or  adult.  In  some  species  the  eggs  hatch  a  few 
hours  after  being  laid,  while  in  others  they  remain  over 
winter.  The  larva  of  most  species,  except  those  of  the 
measuring  worms,  have  eight  pairs  of  legs  of  which  the 
three  anterior  are  known  as  true  legs  because  they  become 


LEPIDOPTERA  91 

the  legs  in  the  imago.  The  others  are  called  false  or  prop 
legs.  The  larva  is  a  voracious  creature,  often  eating  its 
own  weight  of  food  in  a  day.  Its  senses  of  taste  and  feel- 
ing are  well  developed,  but  the  other  senses  appear  quite 
rudimentary.  Three  simple  eyes  on  either  side  of  the  head 
enable  it  to  discern  light  from  darkness. 

The  shedding  of  the  skin,  called  molting,  occurs  usually 
four  or  five  times,  and  in  many  species  the  last  larval  skin 
forms  the  cocoon  in  which  transformation  to  pupa  and 
adult  is  effected.  The  larvae  of  the  butterflies  never  spin 
cocoons,  but  those  of  the  moths,  with  the  exception  of  the 
ones  pupating  in  the  earth,  generally  form  cocoons  either 
from  the  hair  on  their  bodies  or  from  the  secretion  of  cer- 
tain glands.  The  larval  state  in  most  species  continues 
one  or  two  months,  but  in  certain  species  it  lasts  more  than 
a  year.  In  the  pupal  stage  the  insect  appears  as  if  dead. 
Freezing  temperature  for  months  does  not  harm  it.  The 
period  during  which  the  various  species  remain  in  this  con- 
dition is  from  a  few  days  to  a  year.  The  imago  of  many 
species  takes  no  food,  while  in  others,  such  as  the  hawk 
moths  and  some  butterflies,  it  sips  nectar  or  sap  through 
its  proboscis  formed  by  the  greatly  developed  maxilla?. 
The  mandibles  which  chew  the  food  in  the  larval  state  are 
too  small  for  use. 

5.   HEMIPTERA 

The  members  of  this  order  are  the  true  bugs  whose  mouth 
parts  are  adapted  for  piercing  and  sucking.  They  can  not 
bite  or  chew.  Nearly  thirty  thousand  species  have  been 
described,  and  among  them  are  found  the  greatest  enemies 
of  the  human  race. 


ARTHROPOD A 


FIG.  97.  —  Seventeen-year  cicadas  ascending  an  ash  tree  at  8  P.  M.    Flash  light 
photograph,  one  fourth  natural  size. 


HEMIPTERA 


Harvest  Flies  (Cicadidae) 

The  cicadas,  wrongly  called  locusts,  are  the  largest  repre- 
sentatives of  this  order.  The  most  celebrated  of  the  several 
species  is  the  seventeen-year  locust  (Cicada  septendecim) , 


FIG.  98. —Seven teen-year  cicada  showing  metamorphosis  from  nymph  to  adult  as 
it  occurred  between  the  hours  of  9  P.  M.  and  10.30  P.M.  Flashlight  photographs, 
one  half  natural  size. 

which  appeared  in  vast  numbers  in  seventeen  states  during 
1902.  During  the  last  days  of  May  just  at  sundown  under 
the  trees  the  numerous  young,  called 
nymphs,  peeped  out  of  holes  in  the  earth, 
and  a  few  minutes  later  came  forth,  walked 
to  the  nearest  tree,  ascended  some  dis- 
tance, and  fixed  their  claws  firmly  in  the 
bark  in  preparation  for  molting.  A  fis- 
sure appeared  in  the  skin  of  the  backs 
from  which  issued  the  adult  white  cicadas. 
The  wings  slowly  expanded  and  the 
changed  creatures  proceeded  toward  the 
upper  branches,  where  at  daylight  they 
became  of  a  dark  hue  and  forced  their  beaks 
through  the  tender  bark  in  quest  of  sap. 
In  July  the  love  song  of  the  males,  sounding  much 
like  the  rattle  of  the  rattlesnake,  made  such  a  din  in  the 


FIG.  99.  —  Seven- 
teen-year cicada. 
Natural  size. 


ARTHROPODA 


FIG.  100.  — End  of  the  ovipositor  of  a  cicada  showing  below  the  two  saws  used  to 
make  the  insertion  for  the  eggs.    Photograph  enlarged  twenty  times. 


FIG.  101.  — Annual  cicada  with  its  beak  inserted  in 
a  twig. 


forests    that    a   person   could   not    hear   his  companion 

speak  at  a  distance 

of    ten    feet.      The 

noise  is  produced  by 

the    drum    present 

only    in    the    male 

beneath    the    front 

part  of  the  abdo- 
men. A  few  days 

later     the     females 

with  the  saws  of  the  ovipositor  cut  slits  in  the  tender 
branches  to  deposit  numerous  eggs  which 
hatched  a  few  days  later,  and  the  antlike 
young  descended  into  the  earth  to  re- 
main sixteen  years  feeding  on  the  sap 
in  the  roots  or  absorbing  nourishment 
from  the  humus  in  the  soil.  These 
insects  never  sting,  as  many  suppose, 
and  cause  but  little  damage  to  trees. 

FIG.  102. -Pupa  skin  The  annual  cicada  (Cicada  tibicen), 
also  known  as  the  jar  fly  or  dog-day  fly, 


HEMIPTERA 


95 


because  it  appears  in  August,  completes  its  life  round  in 
only  two  years.  The  numerous  pupal  or  nymph  cases 
seen  on  the  trees  in  late  summer  are  of  this  species. 

Plant  Lice  (Aphidae) 

The  plant  lice  have  a  remarkable  life  history.     Most 
of  them  pass  the  winter  in  the  egg  state.     At  the  first 


FlQ,  103.  —  Eggs  of  plant  lice  on  a  maple  tree  in  October.     Photograph  three  times 
natural  size. 

appearance  of  leaves  in  the  spring,  the  eggs  hatch  into 
wingless  females,  no  males  being  found  until  late  in  summer. 


96 


ARTHROPODA 


The  females  bring  forth  living  young  at  the  rate  of  from 
three  to  ten  daily  for  nearly  a  fortnight  and  sometimes 
longer.  In  two  weeks  after  birth  the  young  generations 
are  sufficiently  mature  to  become  the  mothers  of  several 
daughters  daily.  Later  in  the  season  some  of  these  develop 
wings,  and  at  the  approach  of  cold  weather  males  are  born, 


FIG.   104.  —  Plant  lice.     Those  on  the  left  are  enlarged  twice,  tho; 
sucking  juice  are  natural  size.    Photographs. 


at   ihe  right 


some  of  which  also  have  wings.  In  October  and  Novem- 
ber, the  female  deposits  numerous  fertile  eggs  which  re- 
main over  winter  and  hatch  into  stem  mothers  the 
following  season.  So  rapidly  do  the  plant  lice  breed  that 
were  it  not  for  their  natural  enemies,  the  birds,  minute 
parasitic  flies,  syrphus  flies,  and  lady  bugs,  they  would 
destroy  most  of  the  vegetation. 


HEMIPTERA 


97 


The  grape-vine  louse  (Phylloxera  vastatrix)  is  said  to  have 
cost  the  French  more  than  the  indemnity  paid  to  the  Ger- 
mans after  the  Franco-Prussian  war.  Its  damage  in  this 
country  is  not  great. 

The  hop  louse  (Phorodon  humuli)  is  the  great  enemy  of 
the  hop  industry.  Aphis  rosce  makes  the  raising  of  roses 


FlG.  105.  —Grape-vine  Phylloxera  ;  a,  adult ;  b,  young.    After  Marlatt. 

difficult  in  some  regions.  The  maple  louse  blights  young 
maples.  Aphis  mail  stunts  many  young  apple  trees.  The 
cherry  aphis  (Myzus  cerasi)  lives  on  the  cherry  from  April 
till  June,  and  feeds  on  another  plant  the  rest  of  the  season. 
The  green  pea  louse  along  the  Atlantic  coast  in  1900  de- 
stroyed peas  to  the  value  of  four  millions  of  dollars.  In 
1899  the  wheat  louse  damaged  the  wheat  badly  in  many 
sections. 


98 


ARTHROPODA 


The  several  species  of  Aphidse  bearing  a  white  cottony 
growth  are  known  as  wooly  plant  lice.  In  all  there  are 
over  a  thousand  species  of  Aphidae.  Many  of  them  give 
forth  from  the  alimentary  canal  a  honey  dew  much  sought 
after  by  the  ants,  which  often  care  for  the  eggs  and  young 


FIG.  106.  — Hop  louse  which  lives  on  the  plum  tree  in  late  fall,  winter,  and  early 
spring  until  the  hop  vines  develop ;  a,  male ;  b,  female.  Enlarged  twenty 
times.  After  Biley. 

of  the  lice  by  carrying  them  from  place  to  place  and  other- 
wise protecting  them.  Plant  lice  are  therefore  spoken  of 
as  the  ants'  cows. 

Scale  Insects  or  Bark  Lice  (Coccidae) 

The  individuals  of  this  family  are  easily  recognized  by 
the  fact  that  the  female  and  sometimes  the  male  dwell 
beneath  a  scale  varying  in  size  from  one  fiftieth  of  an  inch 
to  a  fourth  of  an  inch  in  diameter.  The  scale  is  formed 
by  the  molted  skins  and  excretions  of  the  insect. 

Pernicious  or  San  Jose  Scale  (Aspidiotus  perniciosus.)  — 


HEMIPTEBA 


This  scale  may  be  studied  to  the  best  advantage  from  July 
to  November.  It  is  distinguished  by  its  circular  form  with 
a  minute  peak  at  the  center,  and  a  red  color  beneath  the 


FIG.  107.  — San  Jose  scale.  The  two  limbs  at  the  right  are  completely  covered, 
while  the  one  at  the  left  has  only  five  large  scales  and  several  small  ones. 
Photograph  ten  times  natural  size. 

bark  or  fruit  supporting  it.  The  scales  may  not  be  per- 
fectly round,  especially  on  the  leaves,  and  the  peak  may 
be  absent  on  some  of  them.  The  insect  winters  in  a  half- 
grown  state,  being  a  mere  disk  of  yellow  covered  by  a 
minute  black  scale.  It  begins  to  feed  in  the  early  spring 
by  sucking  the  sap  through  its  beak  so  tightly  stuck  in  the 
twig  that  it  can  never  be  withdrawn.  By  June  numerous 
young  may  be  seen  within  the  mother  if  examined  under 


100  ARTHROPODA 

the  microscope,  and  during  the  latter  part  of  the  month 
in  the  latitude  of  Pittsburgh  they  give  birth  to  living 
young  which  crawl  out  from  the  scale,  and  during  the  next 


FIG.  108.  — San  Jose  scale  on  a  pear.    Photograph  natural  size. 

two  days  appear  to  the  naked  eye  as  minute  yellowish 
specks  slowly  wandering  over  the  branches.  After  a  free 
life  of  about  forty  hours,  these  Iarva3  insert  the  beak  firmly 
into  the  bark  from  which  they  never  remove  it.  The 
exudations  of  the  insect's  body  form  the  scale.  The  young 
are  ready  to  reproduce  in  one  month,  and  bring  forth  during 
the  next  three  weeks  about  five  hundred  living  young. 


HEMIFPERA, 


101 


As  from  three  to  six  broods  mature  during  a  season,  a 
single  insect  may  be  the  mother  of  one  hundred  million 
young  from  June  to  De- 
cember. 

Their  only  way  of  spread- 
ing is  by  being  carried  on 
the  feet  of  birds,  by  various 
insects,  and  by  the  wind. 
The  purchasing  of  infested 
trees  may  also  be  the  means 
of  introducing  the  pest  into 
a  locality.  It  attacks  most 
fruit  trees,  currant  bushes, 
English  walnut,  osage 
orange,  and  numerous  other 
shrubs,  which  are  usually 
killed  within  two  or  three 
years  by  the  poison  in- 
jected into  them  and  the  loss  of  the  sap.  The  greatest 

natural  enemy 
of  this  scale  is 
the  two-spotted 
ladybird  beetle 
brought  by  the 
go vernmen  t 
agents  from 
China,  the  home 
of  the  scale.  Nu- 
merous artificial 
remedies,  direc- 

FIQ,  110.  — Male  San  Jose  scale  insect  enlarged  about         ,-  /. 

fifty  diameters.    After  Howard.  tlOIlS      101    USlBg 


PIG.  109.  — Female  San  Jose  scale  insect 
removed  from  the  scale.  Several 
young  are  seen  within.  Enlarged 
fifty  diameters.  After  Howard. 


102 


ARTHROPOD  A 


which   may  be   secured  free    from    the   United   States 
Department  of  Agriculture,  will  keep  the  pest  in  check. 


FlG.  111.  — Asiatic  lady- 
bird imported  to  de- 
vour the  San  Jose 
scale,  c,  larva  ;  /, 
adult.  Enlarged  four 
times.  After  Marlatt. 


FIG.  112.  —  Oyster-shell  scales,  three  of  which 
have  holes  showing  where  Chalcis  flies  es- 
caped after  destroying  the  contents.  Three 
times  natural  size. 


The  oyster-shell  bark  louse  (Mytilaspis  pomorum)  is  not 
so  serious  a  pest  as  the  pernicious  scale.  It  brings  forth 
only  one  brood  annually,  and  remains  over  winter  in  the 
egg  state. 


HEMIPTEKA 


103 


The  scurfy  bark  louse, 
with  a  scale  twice  as 
long  as  wide,  impover- 
ishes the  apple  trees  in 
some  localities.  The 
rose  scale  (Diaspis 
rosce)  is  an  enemy 
of  the  roses  and 
blackberries,  but  it  is 
kept  in  check  by  para- 
sites. 

The  armored  scales 
are  represented  by 
the  maple  scale  and  the 
poplar  or  tulip  tree  scale. 
The  covering  of  the  in- 
sect is  not  a  true  scale, 
but  a  waxy  secretion. 
The  common  hothouse 
mealy  bug  is  also  a  fa- 
miliar species  of  the 
CoccidaB.  The  only 
useful  member  of  this 
large  family  is  the 
cochineal  insect  (Coccus 
cacti)  feeding  on  the 
cactus  in  Mexico,  Cen- 
tral America,  and  other 
tropical  regions.  These 
creatures  are  dried  and 
powdered  to  form  the 


FIG.  113.  —  Rose  scale.  Large  round  ones  are 
females  and  the  few  small  elongate  ones  are 
males.  .Enlarged  thrfce  times. 


104 


ARTHROPODA 


famous    cochineal    dye    from    which    carmine   is   ex- 
tracted. 

The  true  bugs  (Heteroptera)  contain  several  species  of 
considerable  interest  to  man.  They  possess  a  beak  per- 
mitting them  to  feed  on  the  juices  of  plants  or  insects,  or 


FIG.  114.  —  Maple 
scale,  five  adults 
and  many  young. 
Photograph  en- 
larged twice. 


FIG.  115.  —  Bedbug  viewed 
from  the  side  and  back  ;  a, 
beak  used  in  piercing  the 
skin  and  sucking  the  blood. 
Photograph  enlarged  twice. 


on  the  blood  of  vertebrates.  The  wings  when  present 
consist  of  two  pairs.  The  anterior  ones  function  as  elytra 
or  covers,  and  have  the  basal  half  thickened,  a  feature  from 
which  the  name  of  the  order,  Hemiptera  (half-winged), 
is  derived. 

The  bedbug  (Cimex  lectularius),  found  in  all  parts  of  the 
world,  is  able  to  live  a  year  or  more  without  food.    This 


HEMIPTERA  105 

fact,  together  with  its  flat  body  permitting  it  to  hide  in 
the  smallest  crevices,  makes  extermination  difficult  when 
a  house  is  once  infested  with  them.  As  they  have  no 
wings  their  usual  method  of  entering  a  house  is  on  articles 
of  clothing.  The  idea  that  they  are  associated  with  bats 
and  pigeons  is  a  mistaken  one,  although  a  similar  bug  is 
a  parasite  on  the  bats. 

The  assassin  bugs,  many  of  which  have  beaks  strong 
enough  to  pierce  the  human  skin,  include  the  kissing  bugs. 
Of  these  Reduvius  personatus  living  in  dirty  basements 
and  feeding  on  bedbugs  and  roaches,  is  common  throughout 
this  country.  It  is  a  fierce  biter,  occasionally  attacking 
man  and  sometimes  causing  serious  sickness,  owing  to  the 
germs  on  the  dirty  beak. 

The  chinch  bug  (Blissus  leucopterus)  causes  an  annual 
loss  to  the  grain  and  grass  crop  of  nearly  twenty  millions 
of  dollars.     It  passes  the  winter  in 
clumps  of  grass  or  other  protected 
places,  and  in  the  spring  lays  about 
five  hundred  eggs  in  the  grass  sheaths 
near  the  ground.     The  young  as  well 
as   the    adults   are   gregarious.      A 


M 


second  generation  develops  from  eggs  FIG.  ne.  -  photograph  of 
laid  in  August.  The  species  occurs  SJj*^8"  enlarged 
over  the  entire  eastern  half  of  the 

United  States,  but  it  is  most  destructive  in  the  Central 
States,  the  Carolinas,  and  Virginia. 

The  ill-smelling  squash  bug  (Anasa  Iristis)  renders  the 
squash,  melon,  pumpkin,  and  cucumber  crop  an  uncertain 
one  in  many  localities,  while  the  harlequin  cabbage  bug 
destroys  millions  of  cabbage  plants  annually.  The  water 


106 


AKTHROPODA 


boatman  (Notonecta)  and  the  giant  water  bug  (Belostoma) 
are  the  two  common  aquatic  members  of  this  order. 

The  pupil  must  remember  that  there  is  a  wide  difference 
between  bugs  and  beetles  both  in  their  external  appearance 
and  habits.  The  most  significant  difference  in  structure  is 
in  the  mouth  parts,  which  should  be  examined  in  some  large 
bug  such  as  the  squash  bug.  In  this  species  the  piercing 


FIG.  117.  —  Squash  bug  viewed  froiu  the  side  and  back;  6,  beak  used  in  piercing 
and  sucking  the  juice  of  the  vines.     Photograph  enlarged  three  times. 

and  sucking  beak  is  more  than  a  quarter  of  an  inch  long,  and 
is  folded  close  to  the  ventral  side  of  the  body  when  not  in  use. 
At  the  base  of  the  beak  is  the  labrum,  while  in  a  groove  on 
its  upper  part  lie  two  pairs  of  hairlike  processes,  the  shorter 
of  which  are  the  mandibles,  and  the  longer  are  the  max- 
illaB.  The  sheath  inclosing  these  is  made  by  the  labium 
and  labial  palpi.  The  bugs  are  capable  only  of  piercing 
and  sucking  food,  and  can  not  bite. 


COLEOPTERA 


ion 


6.  COLEOPTERA 

The  members  of  this  order  are  distinguished  by  the  pres- 
ence of  elytra  (hardened  wing-covers)  which  meet  in  a 
straight  line  down  the  middle  of  the  back.  More  than 
one  hundred  thousand  species  are  known. 

The  snout  beetles  or  weevils  (Rhyncophora)  comprise  over 
four  thousand  species,  all  of  which  are  injurious.  The 
plum  curculio  (Conotrechelus  nenuphar) 
is  familiar  to  every  one  in  its  larval 
state  as  the  footless  white  grub  present 
in  so  many  plums,  cherries,  and  apricots, 
causing  the  unripe  fruit  to  fall  to  the 
ground.  The  larva  then  enters  the  earth, 
soon  becomes  a  quiescent  pupa,  and  a 
fortnight  later  has  completed  its  trans- 
formation to  an  adult  beetle.  It  may 
be  found  on  the  plum  and  cherry  trees  from  May  until 
August.  An  easy  method  of  col- 
lecting them  is  to  hold  an  open 
umbrella  or  sheet  beneath  the  tree 
and  shake  it  vigorously. 

The  nut  weevil  (Balininus)  is 
easily  recognized  by  its  long  snout. 
Chestnuts  harboring  the  larvse  of 
this  weevil  are  spoken  of  as  being 
wormy.  The  eggs  are  laid  in 
August  or  September,  and  the 
larvae  leaving  the  chestnuts  in  late 
FIG.  119. -Photograph  of  lar-  autumn  enter  the  ground  to  pu- 

va  and  adult  nut  weevil  en-  . 

hree  times,  pate  and  remain  until  the  next 


FIG.  118.— Photograph 
of  plum  curculio  en- 
arged  three  times. 


108 


ARTHROPODA 


FIG.  120. -Pea  weevil ;  a,  adult ;  6,  larva ;  c,pupa. 
Enlarged  five  times.    After  CMttenden. 


season.     The  pea  weevil  (Bruchus)  is  often  found  in  peas 

in  its  larval  state  during  summer  and  autumn,  as  a  pupa 

in  winter,  and  in  the 
adult  form  in  late 
spring,  when  it  comes 
forth  to  lay  its  eggs 
on  the  pods  of  the 
growing  peas.  To 
find  the  weevil  in 
the  fall,  soak  peas 
water  for  a  day. 
This  causes  most  of 

the  affected  seeds  to  float.     The  grain  weevil  (Calandra)  is 

a  pest  in  mills  and  granaries,  devouring  the  inside  of  the 

grains  of  wheat. 
The    cotton-boll 

weevil    (Anthono- 

mus      grandis) 

threatens  to  make 

cotton    raising   a 

very       uncertain 

business.      The 

pest    became    so 

troublesome      in 

Texas    that    the 

governor    offered 

a  reward  of  fifty 

thousand     dollars        FIG.  121.  — Cotton-boll   weevil ;  a,  larva  ;  6,  pupa  ;  c, 
tO     any     One    Who  adUlt'    ^tograph  enlarged  four  times. 

should  discover  a  remedy  to  prevent  the  ravages  of  the  in- 
sect, which  amounted  to  twenty  millions  of  dollars  annually. 


COLEOPTERA 


109 


The  strawberry  weevil  (Anthonomus  signatus)  in  certain 
seasons  has  prevented  the  development  of  more  than  a 
half  crop  of  berries  in  New  Jersey,  Delaware,  Maryland, 


FIG.  122.  --  Straw- 
berry  weevil  en- 
larged seven  diam- 
eters. Alter  Chit- 
tenden. 


FIG.  123.  —  Galleries  of  the  spruce-destroying  beetle 
beneath  the  bark  of  a  spruce  tree.     After  Hopkins. 


the  Carolinas,  and  Virginia.    The  eggs  are  deposited  in 
the  flower  buds,  upon  which  the  grublike  larva  feed  and 
attain  full  size  in  about  a  month. 
The  bark  beetles  are  short-snouted  weevils  which  breed 


110 


ARTHROPODA 


just  beneath  the  bark  of  many  species  of  trees  and  exca- 
vate characteristic  galleries.  It  is  estimated  that  they 
damage  timber  to  the  extent  of  fifty  millions  of  dollars 
annually. 

The  Lamellicorn  Beetles  are  characterized  by  antennae 
ending  in  from  three  to  seven  flat  segments.  They  are 
much  less  destructive  than  the  weevils.  The  commonest 


FlG.  124.  —  Pine-bark  beetle  whose  work  has   made  pine  lumber  expensive  ;    a, 
adult ;  c,  pupa ;  d,  larva.    Small  figures  are  natural  size.    After  Hopkins. 

representative  is  the  May  beetle  or  June  beetle  (Lachnosterna 
fusca)  of  a  brown  color  and  more  than  a  half  an  inch  long. 
It  is  often  attracted  into  the  house  at  night  by  the  lighted 
lamp.  The  eggs  are  laid  on  grass  near  the  ground  where 
they  hatch  into  minute  six-legged  white  grubs  with  brown 
heads.  They  burrow  into  the  earth,  feed  on  the  roots 
of  grasses  for  two  years,  and  having  attained  a  length  of 
nearly  two  inches  are  known  to  most  people  as  white  worms 
or  grubs.  Transformation  to  pupa  occurs  in  the  fall  and 
the  adult  issues  the  following  spring.  The  stag 


COLEOFFERA 


111 


(Lucanus  dama) 
presents  a  life 
liistory  similar 
to  the  June 
beetle,  but  the 
larval  and  pupal 
stages  are  passed 
in  decaying 
wood. 

TheLongicorn 
Beetles  (Ceram- 
bycidce)  form  a 
family  including 
eight  thousand 
species  whose 
larva?  are  wood 
borers  tunneling 
through  trees. 

TVi        orl    If  FlG.  125.  —  Stag  beetle;  a,  antenna ;  e,  eye;  m,  mandible 

p,  palpus.    Photograph  natural  size. 

characterized  by 

long,  many-jointed  antennse.  The  locust  borer  (Clytus 

robinice),  whose  white, 
grublike  larva  lives  in 
the  locust  tree,  may  be 
found  in  September  on 
the  golden  rods.  The 
apple  tree  borer  issues 
as  an  adult  from  the 
apple  tree  in  July  and 
FIG.  126. — Larva  of  the  stag  beetle.  Black  may  be  recognized  by 

spots  on  the  side  are  spiracles.    Photograph         .  ,,        .   ,  .      ' 

natural  size.  the  two  yellowish  stripes 


112 


ARTHROPODA 


on  its  elytra.  The  pine  tree  borer  may  live  in  wood 
made  into  furniture  for  fifteen  years.  The  maple  borer 
destroys  annually  many  maple  trees.  It  is  well  for  the 


FIG.    127. —  Beetle  of 
the  locust  borer. 


FlG.    128.  — Firefly  or  Lightning   bug;    a,  larva;  6, 
pupa ;  c,  adult. 


pupil  to  remember  that  not  only  the  larvae  of  many 
beetles,  but  also  the  Iarva3  of  some  of  tjie  Lepidoptera 
and  Hymen  optera  dwell 
within  living  trees. 

The  Serricorn  Beetles 
including  several  thou- 
sand species,  have  ser- 
rate antennae  of  me- 
dium length.  The  larvse 
vary  in  their  habits. 
The  firefly  or  lightning 
bug  (Photinus  pyralis) 
passes  its  larval  life  in 
the  earth  feeding  on 

,,  ,          -,  FIG,    129. —  Click    beetle    and    its    larva, 

earth    WOrmS    and    SOtt-  Slightly  enlarged. 

bodied  insects.      It  pu- 
pates in  a  cocoon  of  earth,  and  transforms  to  the  adult 
state  in  June,  when  it  comes  forth  and  flies  about  by  night 
emitting  a  strong  light  from  the  lower  side  of  the  posterior 


COLEOPTERA 


118 


part  of  the  abdomen.    The  larva  of  a  larger  species  lives 
above  ground  and  is  known  as  the  glow  worm. 

The  click  beetles,  making  up  the  family  Elateridse,  may 
be  recognized  by  the  characteristic 
click  which  they  give  to  right  them- 
selves when  placed  on  their  backs. 
The  larvae,  called  wire  worms,  live  under 
the  bark  of  trees,  in  rotten  wood,  or 
upon  the  roots  of  herbs.  They  have 
a  rather  hard,  brownish  skin  and  three 
pairs  of  legs.  They  are  plentiful  and 
easily  found  in  rotten  logs.  In  summer 
and  autumn  the  beetles  feed  on  the 
flowers. 

TO,       ni       •  T>      Ai  i,  i.  FIG.  130.  — Eyed  elater, 

The  Clavicorn  Beetles  are  character-       the  largest  of  the  click 
ized    by    club-shaped   antenna.     The        befles:  .phot°graPh 

J  natural  size. 

buffalo  moth  or  carpet  beetle  (Anthrenus 

scrophularice)  is  present  in  nearly  every  house  with  tacked- 


FIG.  131. — Buffalo  moth  or  carpet  beetle;  a,  larva;  b,  pupa  within  larva  skin; 
c,  pupa ;  d,  adult.     Enlarged  eight  times.     After  Riley. 

down  woolen  carpets.    The  small  larva  bristling  with  brown 
hairs  may  be  found  under  the  edge  of  a  carpet  not  recently 


114 


ARTHROPODA 


FIG.  132.  —Museum  pest  (Anthrenus  varius).  Larva 
below  the  open  pupa  case,  and  adult  above. 
Photograph  enlarged  three  times. 


cleaned,  at  almost  any  time  of  the  year.  It  feeds  on  any 
kind  of  woolen  material.  It  is  probable  that  there  are  two 
broods  a  year,  but  the  beetles  are  most  frequently  seen  on 

the  windows  in 
April.  A  similar 
beetle,  the  museum 
pest  (Anthrenus  va- 
rius),  destroys 
many  kinds  of 
dried  museum  ma- 
terial. Carbon  bi- 
sulphide, a  fourth 
of  an  ounce  to  each 
cubic  foot,  will  de- 
stroy any  of  these 
beetles  or  their 
Iarva3  if  the  box  or  closet  containing  them  is  closed 
tightly  for  a  day. 
The  ladybird  fam- 
ily (CoccinellidcB), 
containing  about  a 
thousand  species, 
should  be  known 
to  every  one,  as 
nearly  all  of  its 
members  are 
friends  of  man. 
They  are  of  a  more 
or  less  hemispheri- 
cal form,  and  usually  of  a  red  or  yellow  color  with 
round  or  lunate  black  spots.  The  larvae,  which  are 


FIG.  133.  —  Ladybird  beetle;  a,  larva;  6,  pupa;  c, 
adult.  Line  at  the  right  shows  natural  size.  After 
Chittenden. 


COLEOPTERA  115 

most   abundant  in   June  and  July,  consume  great  num- 
bers of  plant  lice.     In  some  places  in. California  the  de- 
structive orange  scale   has   been   entirely  kept   in  check 
by  a  species  of  ladybird  beetle,  and  lately 
the  Asiatic  ladybird  imported  from  China 
is  proving  a  great   destroyer  of  the  San 
Jose  scale.     The  beetles  pass  the  winter 
in    the    adult    state,   often   coming    into 
houses,  where  they  should  be  protected.          Fm        —Larva 
The  Leaf-eating  Beetles,  numbering  ten        of  ladybird  bee- 

,,  -.  ...  ,  tie    twice    natu- 

thousand  species,  are  injurious  to  garden  raisize. 
vegetables  and  many  shade  trees.  The 
best  known  of  these  are  the  Colorado  potato  beetle,  the 
asparagus  beetle,  and  the  elm  leaf  beetle,  whose  depredations 
cost  millions  of  dollars  annually.  The  Colorado  potato 
beetle  dwelt  near  the  base  of  the  Rocky  Mountains  until 
1859  when  it  began  to  be  a  pest  in  the  potato  fields  of  the 
western  settlers.  Having  acquired  the  habit  of  feeding 
upon  the  potato,  it  spread  rapidly,  reaching  the  Atlantic 
coast  in  1874.  The  pest  is  easily  kept  in  check  by  spray- 
ing the  potatoes  with  Paris  green  and  water  or  sprinkling 
them  with  fifteen  parts  of  flour  to  one  part  of  Paris  green. 
The  Coleoptera  exhibit  a  complete  metamorphosis,  but 
the  forms  and  habits  of  the  larvae  vary  widely.  Some  dwell 
underground,  some  thrive  on  decaying  wood,  and  some 
prey  on  other  insects.  With  the  exception  of  the  lady- 
birds, and  carrion  beetles  whose  larvae  feed  on  decaying 
flesh,  the  members  of  this  order  are  mostly  injurious. 
Instead  of  taking  food  by  sucking,  as  is  the  habit  of  all  the 
bugs,  they  chew  their  food  and  are  therefore  readily  killed 
by  spraying  the  vegetation  with  poisons. 


116 


ARTHROPODA 


7.   NEUROPTERA,   EPHEMERIDA,   AND   ODONATA 

A  typical  example  of  the  Neuroptera  is  the  hellgramite 
(Corydalis  cornutus)  whose  larva,  the  black  crab,  or  dobson, 

is  the  f  a  v  o  r  it  e 
among  fishermen  as 
a  bait  for  black 
bass.  It  is  found 
under  logs  and 
stones  in  the  shal- 
low water  of  clear 
streams,  which  it 
leaves  in  late  spring 
to  hide  under  some 
object  on  the  bank 
and  to  transform  to 
a  naked  pupa.  A 
week  or  more  later 
it  assumes  the  adult 
form  which  may 

FIG.  135.  -  Catching  the  larv*  of  hellgramites.         ^^         ^        ^^ 

around  the  electric   lights  at  night.    The  egg  deposits 
form  conspicuous  white   spots   the   size    of  a  nickel  on 


FIG.  136.  —  The  dobson,  natural  size. 


NEUROPTEEA,   EPHEMER1DA,  AND  ODONATA       117 


the  lower  sides  of  logs,  rocks,  and  trees  overhanging 
the  water,  where  they  may  be  found  during  June 
and  July.  The  young  drop  into  the  water,  and  during 
the  larval  stage  of 
nearly  three  years  feed 
on  aquatic  insects. 
Respiration  is^  accom- 
plished by  the  several 
pairs  of  tufts  on  either 
side  of  the  abdomen. 

Other  well-known 
members  of  this  order 
are  the  ant-lion  and  the 
aphis-lions  or  lace-wing 
flies.  The  larvae  of 
these  as  the  names  suggest  feed  upon  ants  and  plant  lice, 


FlG*  137-PuPa  of 


bellgramite,  natural 


FIG.  138.  —  Hellgramite,  natural  size. 

and  may  be  found  in  places  frequented  by  their  prey  in 
June  and  July. 

The  May  Flies  (Ephemerida) . — The  members  of  this 
order  are  distinguished  by  their  short  antennae,  large  front 
wings  and  small  hind  ones,  and  two  or  three  slender  fila- 


118  ARTHROPOD  A 

ments  at  the  end  of  the  abdomen.  The  larvae  of  all  the 
species  live  in  the  water,  feed  upon  vegetable  matter,  and 
breathe  by  means  of  gill  tufts.  The  larval  life  lasts  from 
one  to  three  years  during  which  large  numbers  are  eaten 
by  fish.  Metamorphosis  to  the  adult  form  takes  place  in 
May  and  June  when  the  adults  sometimes  become  so  numer- 
ous along  the  watercourses  that  the  dead  may  be  picked  up 
by  the  handfuls  where  the  waves  wash  them  up  on  the 


FIG.  139.  —  May  fly,  twice  natural  size. 

shore.  The  pupa  or  nymph  is  active  and  much  like  the 
larva  in  form,  except  wing  pads  are  present. 

The  adults  take  no  food  as  the  mouth  parts  are  atrophied 
and  the  alimentary  canal  is  not  fitted  for  digestion.  They 
usually  live  only  a  day  or  two. 

Dragon  Flies  (Odonata).  —  All  the  numerous  species  of 
this  order  have  a  similar  life  history  which  is  easily  studied 
in  any  one  of  our  dozen  common  kinds.  The  nymph  or 
larval  stage  may  be  found  almost  any  time  of  the  year  in 
mud  at  the  bottom  of  ponds,  and  if  large  specimens  are 
removed  to  the  aquarium  in  May  and  fed  daily  with  fresh 


NEUKOPTERA,  EPHEMERIDA,  AND  ODONATA   119 

beef,  mosquito  larvse,  or  bits  of  earth  worm  they  will  be 
seen  to  molt.  In  some  cases  the  nymph  (pupa)  will  climb 
a  stick  or  stem  of  a  water  plant  during  a  night  in  June,  and 
early  the  following  morning  from  a  sli t  in  the  skin  of  its 
back  the  adult  insect  will  come  forth.  In  midsummer 


FIG.  140.  —  Dragon  fly  and  larva  (Plathemis  lydia).     Photograph  natural  size. 

the  eggs  are  laid  on  the  surface  of  the  water  or  on  some 
object  beneath  the  surface. 

Most  dragon  flies  alight  with  expanded  wings,  but  a 
group  of  the  more  slender-bodied  ones  resting  with  wings 
folded  goes  under  the  name  of  damsel  flies.  So  far  as  known 
all  dragon  flies,  otherwise  called  devil's  darning  needles, 
snake  feeders,  and  snake  doctors,  are  harmless  and  bene- 
ficial insects.  The  larvae  feed  on  mosquito  larvae  and  other 
aquatic  forms,  while  the  mature  insect  consumes  large 
numbers  of  mosquitoes.  To  note  one's  appetite  hold  it  by 


120 


ARTHROPODA 


FIG  .  141.  —  Photograph  of  a  damsel  fly  just  out  of  the  pupal  skin  below.    Natural  size. 

the  wings  pressed  together  over  its  back  and  feed  it  house 
flies  of  which  it  will  devour  as  many  as  two  dozen  hi  a  few 
minutes. 


Characteristic  Features  of  Insects 

The  insects  agree  in  having  a  segmented  body  composed 
of  three  clearly  defined  parts,  the  head,  thorax,  and  abdo- 
men. The  head  bears  two  hairlike  processes,  the  antenna?, 
a  pair  of  large  compound  eyes,  and  several  ocelli  or  simple 
eyes.  The  wings  varying  in  number  from  none  to  two 
pairs  are  attached  to  the  thorax  and  present  nervures  or 
veins.  These  are  air  tubes  or  tracheae.  The  legs,  of  which 


NEUROPTERA,  EPHEMERIDA,  AND  ODONATA   121 


FIG.  142.  —  Photograph  of  a  model  to  show  the  structure  of  the  honey  bee;  a, 
salivary  gland  ;  b,  brain  ;  e,  esophagus  ;  h,  honey  stomach  ;  hr,  heart  with  five 
cross  slits  through  which  the  blood  enters  ;  t,  tongue  ;  m,  mandible  ;  mx,  max- 
illa ;  n,  one  of  the  eight  ventral  ganglia  made  of  nerve  cells  and  connected  by 
white  nerve  cords  ;  p,  poison  gland  ;  r,  rectum  or  end-portion  of  the  intestine  ; 
rt,  aorta  or  mainblood  vessel ;  s,  true  stomach  ;  st,  sting  ;  t,  intestine  surrounded 
by  white  tubes,  the  kidneys  ;  u,  ventral  head  ganglion. 

there  are  never  more  than  three  pairs,  are  joined  to  the 
thorax.  All  insects  having  a  complete  metamorphosis 
pass  through  four  stages  in  their  life  history  known  as  the 
egg,  larva,  pupa,  and  imago.  Some  forms,  such  as  the 
Orthoptera,  Hemiptera  and  Odonata,  are  said  to  exhibit 
an  incomplete  metamorphosis  because  the  difference  in 
form  between  the  larva  and  pupa  is  not  very  marked.  The 
young  of  these  orders  is  therefore  often  called  a  nymph. 
The  larval  form  of  the  Lepidoptera  is  named  a  caterpillar , 


122  ARTHKOPODA 

that  of  the  Coleoptera,  a  grub;  that  of  the  Diptera,  a 
maggot.  The  larva  of  some  families  has  as  many  as  six- 
teen legs,  while  in  others  there  are  from  six  to  twelve,  and 
in  the  weevils  no  legs  are  present. 

As  the  structure  of  the  various  insects  is  so  similar,  a 


FIG.  143.  —  Diagrammatic  cross  section  of  a  grasshopper  enlarged  three  times  ;  h, 
chief  blood  vessel ;  i,  intestine  ;  «,  ganglion  of  the  nerve  cord  ;  t,  stigmata  or 
spiracle  for  the  admission  of  air  to  the  branched  tracheal  tubes  ;  w,  wings  ;  a, 
coxa ;  ft,  trochanter ;  c,  femur  ;  d,  tibia ;  e,  tarsus. 


study  of  any  form  will  serve  to  give  a  general  knowledge 
of  the  anatomy  of  all.  Large  locusts  or  grasshoppers  are 
easily  secured,  and  can  be  dissected  to  advantage  if  pre- 
served in  seventy  per  cent  alcohol  (commercial  alcohol 
three  parts  and  water  one  part).  To  dissect,  place  in  a  pan 
with  water  sufficient  to  cover  and  fix  to  the  wax-covered 


NEUROPTERA,  EPHEMERIDA,  AND  ODONATA    123 

bottom  with  two  pins,  the  one  passing  very  obliquely 
through  the  head  and  the  other  through  the  hind  part  of 
the  abdomen.  Cut  away  with  scissors  the  dorsal  portion 
of  the  body  wall  and  immediately  beneath  it  note  a  light- 
colored  threadlike  tube,  which  is  the  heart.  Ramifying 
among  the  muscles  are  the  trachea  appearing  as  minute 
slender  white  tubes,  which  examined  in  a  drop  of  water 
under  the  microscope  show  spiral  thickenings.  If  near 
egg-laying  time  the  female  will  have  much  of  her  ab- 
domen filled  with  the  two  ovaries  containing  many  eggs. 
Two  small  tubes,  the  oviducts,  pass  from  the  ovaries  to 
the  posterior  ventral  side  of  the  abdomen,  where  they 
unite. 

The  digestive  canal  is  a  tube  extending  in  an  al- 
most straight  course  from  the  mouth  to  the  posterior 
end  of  the  body.  The  much  enlarged  portion  in  the 
thorax  is  the  crop  which  receives  the  food  from  the 
esophagus  opening  from  the  mouth.  The  stomach  lies 
next  to  the  crop  and  leads  into  the  intestine.  Several 
blind  pouches,  called  ca&ca,  project  forward  from  the 
stomach. 

The  nervous  system  is  not  easy  to  observe,  but  if  all  the 
other  organs  are  removed  from  the  body,  a  white  mass  of 
nerve  matter,  a  ganglion,  about  the  size  of  a  pinhead  may 
be  found  on  the  floor  of  the  thorax  and  from  it  two  nerve 
cords  extending  forward  to  the  mouth  where  they  pass 
around  the  esophagus  to  a  large  ganglion,  named  the  brain. 
Two  cords  also  pass  backward  from  the  thoracic  ganglion 
through  the  abdomen  and  bear  several  ganglia.  All  ganglia 
are  collections  of  nerve  cells,  whose  processes,  the  fibers, 
form  the  cords. 


124  ARTHROPODA 

Importance  of  Studying  the  Insects 

The  necessity  of  investigating  the  habits  and  structure 
of  insects  in  order  that  we  may  be  able  to  control  them  is 
well  presented  in  the  following  abstracts  taken  from  the 
writings  of  Slingerland: 

A  very  conservative  estimate  puts  the  yearly  loss  from 
insect  depredations  in  the  United  States  at  one  tenth  of  all 
the  farm  crops,  and  this  amounts  to  the  enormous  sum  of 
$300,000,000,  and  this  is  only  about  $52  for  each  farm.  A 
recent  estimate  by  experts  put  the  yearly  loss  from  forest 
insect  depredations  at  not  less  than  $100,000,000.  The 
common  schools  of  the  country  cost  in  1902  the  sum  of 
$235,000,000,  and  all  higher  institutions  of  learning  cost 
less  than  $50,000,000,  making  the  total  cost  of  education 
in  the  United  States  considerably  less  than  the  farmers 
lost  from  insect  ravages. 

Furthermore,  the  yearly  losses  from  insect  ravages  aggre- 
gate nearly  twice  as  much  as  it  costs  to  maintain  our  army 
and  navy;  more  than  twice  the  loss  by  fire;  twice  the  capital 
invested  in  manufacturing  agricultural  implements;  and 
nearly  three  times  the  estimated  value  of  the  products  of 
all  the  fruit  orchards,  vineyards,  and  small  fruit  farms  in 
the  country. 

We  dare  not  hazard  a  guess  and  have  no  data  on  which 
to  base  an  estimate  as  to  how  much  American  farmers  are 
now  spending  in  time  and  money  in  the  warfare  against 
their  insect  enemies.  It  would  surely  aggregate  a  sum 
that  would  startle  us.  But  at  least  one  hundred  and  twenty- 
five  entomological  workers  are  now  devoting  most  of  their 
energies  and  spending  probably  $250,000  in  the  United 


ARACHNIDA   AND   MYEIAPODA  125 

States  in  studying  injurious  insects  and  devising  methods 
for  preventing  such  enormous  losses  to  American  farmers. 
Massachusetts  spent  more  than  a  million  dollars  in  trying 
to  exterminate  the  gypsy  moth,  and  Congress  has  just 
appropriated  $250,000  to  fight  the  boll-weevil  and  other 
troubles  in  southern  cotton  fields.  Farmers  are  trying  to 
feed  to  insects  over  two  thousand  tons  of  Paris  green 
annually  in  the  United  States. 

The  statistics  for  New  York  state  also  offer  some  inter- 
esting comparisons  along  this  line.  The  total  value  of  all 
farm  and  forest  crops,  excluding  animal  products,  in  New 
York,  in  1899,  was  $150,000,000,  and  the  one  tenth  that  the 
insects  got  was  worth  $15,000,000.  It  may  seem  incredible 
that  it  costs  such  a  sum  to  feed  New  York's  injurious 
insects  every  year,  but  it  is  an  average  of  only  $66  for  each 
of  the  227,000  farms  in  the  state;  and  there  are  few  farms 
where  the  crops  are  not  lessened  more  than  this  amount 
by  insects.  It  is  admitted  that  the  codling  moth  alone 
ruins  $3,000,000  worth  of  apples  and  pears  yearly  in  the 
state,  and  in  1901  the  Hessian  fly  took  half  of  New  York's 
wheat  crop,  thus  robbing  the  farmers  of  $3,500,000. 


8.  ARACHNIDA  AND   MYRIAPODA 

The  Arachnida,  including  the  spiders,  scorpions,  and 
mites,  are  distinguished  from  other  arthropods  by  the  pres- 
ence of  four  pairs  of  legs,  the  division  of  the  body  into  two 
parts,  called  cephalo-thorax  and  abdomen,  and  the  absence 
of  antennae.  From  two  to  six  pairs  of  eyes  are  just  visible 
on  the  upper  part  of  the  forehead.  No  ears  have  been 


126  ARTHROPODA 

found,  and  as  none  of  the  group  make  any  noise  they  prob- 
ably can  not  hear. 

The  first  pair  of  mouth  appendages  are  the  chelicerce, 
terminating  in  claws  at  whose  ends  poison  glands  open. 
The  idea  that  thp  bite  of  a  spider  which  is  made  by  the 
chelicerse  is  dangerous,  has  no  foundation  in  fact.  In  most 
of  our  common  species  the  terminal  claw  is  scarcely  long 
enough  to  reach  through  the  skin,  and  the  poison  is  not 
sufficient  to  cause  any  discomfort.  Occasionally  dirt 


FlG.  144.  —  Agalena,  the  grass  spider.  At  the  right  is  a  photograph  of  its  webs  as 
seen  on  a  dewy  morning ;  at  the  left  the  spider  with  its  cocoon  of  eggs  in  the 
overlapped  leaf  photographed  natural  size. 

getting  access  beneath  the  skin  with  the  poison  may  cause 
an  inflammation.  The  large  spiders  of  the  South,  the  taran- 
tulas, possess  large  fangs  and  enough  poison  to  make  their 
victim  quite  sick. 

The  second  pair  of  mouth  parts,  looking  like  legs,  are  the 
pedipalps.  On  the  ventral  side  of  the  abdomen  near  its 
stalk  attachment  to  the  cephalo-thorax  may  be  seen  a  pair 
or  two  of  slits  opening  into  the  lung  sacs.  These  consist 
of  small  cavities  across  which  hang  about  a  dozen  lamellse 


ARACHNID  A   AND   MYRIAPODA  127 


FIG.  145.  —  Lycosa  on  its  back  ;  p,  poison  fang  ;  s,  spinneret.    Photograph  nat- 
ural size. 


FJG,  146.  —  Lycosa  with  its  cocoon  of  eggs.    Photograph  natural  s 


128 


ABTHROPODA 


or  plates  of  tissue,  in  which  the  blood  circulates  to  give 
off  its  carbon  dioxide  and  take  up  oxygen  necessary  for 
the  life  of  every  part  of  the  body. 

The  spiders  are  divided  into  two  groups,  the  spinners, 
or  sedentary  spiders,  and 
the  non-spinners,  or  wander- 
ing spiders.  Of  the  spinners 
there  are  four  kinds. 

The  tunnel  weavers  are 
those  which  make  tubes  in 
the  earth  and  line  them 
with  silk.  Some  such  as  the 
trapdoor  spiders  of  Texas 
and  California  have  suffi- 
cient skill  to  make  a  door  to 
close  the  entrance  against 
intruders. 

The  tube  weavers  make 
the  webs  so  conspicuous 
in  the  grass  on  a  dewy 
morning.  At  one  side  of 
the  web  a  tube  extends 
toward  the  ground.  Some 
of  these  species  spin  quite 
deserted  buildings  and  in 


FIG.  147.  —  Photograph  of  the  nest  of  a 
Texas  trapdoor  spider  with  the  door 
open  to  the  left. 


Of 


dense    webs   in    corners 
bushes. 

The  line  weavers  are  those  which  construct  irregular 
webs  known  as  cobwebs. 

The  orb  weavers  work  with  mathematical  precision,  spin- 
ning spirals  supported  by  numerous  radii.  The  male  orb- 
weaving  spider  is  much  smaller  than  the  female  which 


ARACHNIDA  AND   MYRIAPODA  129 

sometimes  becomes  so  angered  with  her  mate  as  to  kill 
and  eat  him. 

The  silk  with  which  spiders  work  is  formed  by  glands 
in  the  abdomen,  which  open  by  two  or  three  pairs  of  promi- 
nences, the  spinnerets  at  the  posterior  part  of  the  abdomen. 
The  excretion  passing  out  of  these  several  orifices  unites 


Fia.  148.  — Epeira,  the  common  garden  spider  on  its  web.     Photograph  one  half 
natural  size  by  Charles  Morris. 

to  form  a  single  thread.    The  chief  use  of  spiders'  silk  is 
for  cross  hairs  in  telescopes. 

The  wandering  spiders  never  spin  complete  webs,  but 
wander  about  buildings  and  fields.  Our  common  species 
are  rather  large,  and  the  female  carries  with  her  the  small, 
round  cocoon  containing  the  eggs  or  young.  Most  spiders 
deposit  their  eggs,  often  numbering  nearly  a  hundred,  in 
cocoons,  where  they  hatch  in  about  two  weeks,  and  the 
stronger  young  prey  on  the  weaker  for  several  days,  so 


130 


ARTHROPODA 


that  not  more  than  a  dozen   individuals   survive.      In 
some  species  the  young  pass  the  winter  in  the  cocoon. 


FlG.  149.  — Argiope,  the  large  orb  weaver  just  completing  the  spinning  of  the  wind- 
ing stair.    Photograph  two  thirds  natural  size. 

The  harvestmen  or  grandady-long-legs  are  beneficial  mem- 
bers of  this  group  as  they  feed  largely  on  harmful  insects. 


ARACHNIDA   AND   MYRIAPODA 


131 


The  itch  mite  (Sar  copies  scabei),  causing  the  itch  in  man, 
and  Demodex  folliculorum,  the  parasite  sometimes  present 


FIG.  150. —  Demodex  folliculorum  enlarged  one  thousand 
times.    After  Selenka. 

in  the  human  hair  follicles,  are  Arachnida  much  changed 
on  account  of  their  parasitic  habits.     The  minute  jigger 


FIG.  151.  — Scorpion  showing  the  sting  at  the  posterior  end.    Photograph  natural 
size. 

or  chigger,  so  numerous  in  old  berry  patches  in  the  South- 
ern and  Central  States,  often  causes  great  inconvenience 
by  burying  itself  beneath  the  human  skin. 


132 


ARTHROPODA 


The  scorpions,  usually  with  an  elongated  abdomen  at  the 
end  of  which  is  a  sting  and  the  opening  of  a  poison  gland, 
dwell  in  the  warmer  parts  of  our  country  and  other  tropical 
regions. 

Myriapoda 

The  members  of  this  class  are  characterized  by  an 
elongated  body  consisting  of  only  two  regions,  the  head 


FIG.  152.  —  Scutigera  forceps,  a  harmless  centiped.    Natural  size.    After  Marlatt. 


and  trunk.    The  latter  bears  one  or  two  pairs  of  jointed 
feet  on  each  segment.    They  are  divided  into  two  groups, 


FIG.  153.  —  A  poisonous  centiped  from  Texas.    Half  natural  size. 

one  of  which,  the  centipeds,  includes  those  forms  having 
a  single  pair  of  legs  to  each  body  segment,  while  the  other  ? 
the  millepeds,  have  two  pairs  of  legs  to  each  segment. 


CRUSTACEA  130 

Scutigera  forceps  is  a  common  centiped  seen  running 
about  in  dark  cellars  or  basements.  It  is  entirely  harmless. 
Other  harmless  centipeds  are  found  under  logs  and  stones. 
Scokpendra  is  the  genus  of  the  poisonous  centipeds  of 
the  South,  the  West  Indies,  and  South  America.  They 
are  from  six  to  ten  inches  long,  and  with  their  poison  fangs 
are  capable  of  inflict- 
ing serious  bites  on 
man. 

The  galley  worm 
(Spirobolus),  a  com- 
mon  species  of  mille-  Fm  154<_Galley  worm. 

ped,  lives  under 

stones  and  logs  where  it  feeds  on  dead  snails  and  earth- 
worms. Polydesmus  is  a  flat  milleped  found  in  moist 
places. 

9.    CRUSTACEA 

The  crustaceans  differ  from  the  other  arthropods  in 
usually  breathing  by  gills  and  having  two  pairs  of  antenna. 
Many  forms  possess  a  hard  outer  skin  or  exoskeleton  to 
which  the  name  of  the  class  is  due.  The  fresh  water  cray- 
fish (Cambarus)  and  the  lobster  (Homarus)  are  so  similar 
in  structure  that  a  description  of  one  applies  almost  equally 
well  to  the  other. 

The  body  of  the  crayfish,  bearing  nineteen  pairs  of  appen- 
dages, is  divided  into  a  cephalothorax  and  abdomen.  The 
former,  including  the  head  and  thorax,  is  covered  by  a  cal- 
careous shield,  the  carapace,  which  when  broken  off  on  the 
sides  reveals  the  gills  composed  of  feathery  filaments  with 


134 


ARTHROPODA 


FIG.  155.— Crayfish  or  crawfish  (Cambarus  bartoni).  Photograph  natural  size.  The 
antennae  are  the  two  long  backward  projections  from  the  head  and  the  auten- 
nules  the  short  forward  projections. 


FIG.  156.  —Crayfish  with  the  left  half  of  the  body  structures  removed  ;  a,  intestine  ; 
6,  ventral  artery ;  c,  brain ;  e,  heart ;  et,  gastric  teeth ;  i,  oviduct ;  /,  liver ;  m, 
muscles  ;  n,  green  gland  (kidney)  ;  o,  ovary  ;  p,  pyloric  stomach;  r,  nerve  cords ; 
s,  cardiac  stomach ;  st,  mouth ;  u,  telson ;  wt  openings  of  veins  into  the  pericar- 
dial  sinus.  Twice  natural  size. 

the  bases  of  the  main  stems  attached  below.  A  median 
spine,  the  rostrum,  projects  between  the  eyestalks  support- 
ing the  compound  eyes  on  movable  stalks,  beneath  which 


CRUSTACEA  135 

are  the  antennules  about  one  fourth  as  long  as  the  jointed 
antenna?  proper.  On  the  lower  surface  of  the  basal  joint 
of  each  of  these  is  the  opening  of  the  green  glands  or 
kidneys.  On  the  thorax  are  four  pairs  of  long  slender 
walking  legs,  in  front  of  which  is  a  pair  of  very  large  legs 
called  chelipeds,  terminating  in  pincers,  the  chelce.  Anterior 
to  these  are  three  pairs  of  small  appendages,  the  maxillipeds, 
or  jaw  feet,  of  use  in  feeding. 

The  head  proper  shows  in  the  mouth  region  a  pair  of 
hard  notched  lateral  moving  mandibles  and  behind  them 
two  pairs  of  leaflike  maxillce.  The  second  pair  of  maxillae 
differs  from  the  first  pair  in  having  a  flat  paddle-like 
process,  called  gill  bailer,  used  to  bring  the  water  forward 
from  the  gill  chamber,  in  which  are  the  gills  beneath  the 
carapace.  On  the  ventral  side  of  several  segments  of 
the  abdomen  are  small  appendages,  termed  pleopods  or 
swimmerets,  which  carry  the  eggs  in  the  female.  Each 
pleopod  consists  of  a  basal  piece,  the  protopodite,  and  two 
branches,  the  outer  of  which  is  the  exopodite  and  the  inner 
the  endopodite.  This  is  the  typical  structure  of  a  crusta- 
cean appendage,  but  in  many  cases  it  is  much  modified 
by  use,  as  in  the  walking  legs  where  the  exopodite  is 
wanting. 

By  pinning  down  the  specimen  in  a  waxed-bottom  pan 
full  of  water  and  cutting  off  the  carapace  and  dorsal  por- 
tion of  the  abdomen,  some  of  the  structures  shown  in  the 
figure  may  be  found.  The  male  can  be  distinguished  from 
the  female  by  the  presence  of  the  minute  orifice  of  the 
reproductive  organ  on  the  ventral  side  of  the  last  leg  near 
its  junction  with  the  thorax.  In  the  female  the  opening  is 
on  the  third  leg  from  the  last. 


136  ARTHROPODA 

The  blood  of  the  crayfish,  like  that  of  the  insects,  is  color- 
less. After  circulating  through  the  arteries  and  their 
branches  to  carry  oxygen  and  nourishment  to  all  parts  of 
the  body  it  collects  in  irregular  channels,  called  sinuses, 
lying  between  the  muscles  and  the  other  organs.  From 
the  sinuses,  vessels  lead  the  blood  to  the  gills  on  either  side 
beneath  the  carapace  to  absorb  oxygen  from  the  surround- 
ing water  and  give  off  the  carbon  dioxide  collected  from 
the  tissues  of  the  body.  From  the  gills  the  blood  returns 


FJG.  157.  —Photograph  of  the  lobster  one  third  natural  size. 

to  the  pericardial  sinus  and  enters  the  heart  through  six 
slits  with  valves  opening  inward. 

The  lobster  (Homarus  americanus')  ranges  along  the 
Atlantic  coast  from  Labrador  to  Delaware  Bay.  Of  late 
years  it  has  become  so  scarce  that  laws  have  been  passed 
for  its  protection.  In  Connecticut  none  may  be  caught 
under  six  inches  long,  while  in  New  York  and  Massachu- 
setts they  must  be  not  less  than  ten  and  a  half  inches  in 
length.  At  Cold  Spring  Harbor,  Long  Island,  and  at 
Woods  Hole,  stations  have  been  established  by  the  govern- 
ment for  the  purpose  of  rearing  young  lobsters.  The  eggs, 


CRUSTACEA 


137 


numbering  several  thou- 
sands, are  taken  from  the 
female  which  carries  them 
entangled  among  the  pleo- 
pods  on  the  ventral  side  of 
the  abdomen,  and  hatched 
in  prepared  tanks.  The 
young  are  thus  protected 
from  the  voracious  appe- 
tites Of  marine  fish,  and  FIG.  158.  —  Hermit  crab  (Eupagurus 
,  -•  -.  -,  .  ,.  longicarpus).  Natural  size. 

when  old  enough  to  care  for 

themselves  are  distributed  at  favorable  points  along  the 

coast. 

A  molting  process  takes  place  among  the  crustaceans 


FIG.  159.  —Fiddler  crabs  (Gelasimus  minax).  Note  the  large  fighting  cbela  on  the 
two  specimens  at  the  right.  On  specimen  at  left  it  was  broken  off  and  is  just 
being  renewed.  Photograph  natural  size  by  Overton. 


138 


AKTHROPODA 


similar  to  that  occurring  in  the  larviB  of  insects.    The  hard 
covering  becomes  too  small  for  the  growing  animal,  and 

in   the    lobster    it     ^ 

splits  along  the 
median  dorsal  line, 
while  the  blood 
leaves  the  limbs, 
permitting  them 
to  be  withdrawn 
from  their  case- 
ments. The  lining 
of  the  whole  ali- 
mentary canal  is 
also  shed.  The 
animal  just  before 
molting  is  known 
as  the  black  lobster. 
The  newly  molted 
crab  is  marketed 
under  the  name  of 
soft-shelled  crab. 

The  hermit  crabs 
protect  themselves 
by  living  in  the 
abandoned  shells 
of  some  mollusks, 
and  when  the  in- 
creased size  of  the 
body  makes  the  shell  too  small,  the  animal  seeks  a 
larger  one.  Of  the  edible  crabs,  the  commonest  are  the 
large  blue  crab  (Callinectes  hastatus),  and  the  oyster 


FIG.  160.  —  Photograph  of  Cyclops    enlarged  forty 
times.     An  egg  mass  at  the  right. 


CRUSTACEA 


139 


crab.  (Pinnotheres  ostreum)  the  female  of  which  lives  in 
oysters. 

The  water  fleas  just  visible  to  the  naked  eye  are  present 
in  nearly  all  waters  and 
become  very  abundant 
in  stagnant  water.    The 
common  fresh  water  gen- 
era are    Cypris,    Daph- 
nia,  and  Cyclops.   They 
make  up  a   large  part 
of  the  food  for  young  fish.     Many  species  of  small  crus- 
taceans are  parasites  on  fish  or  other    aquatic  animals, 
and   because  of  their  habits  become  so  changed  in  ap- 


Fm.  161. — Daphnia  enlarged  forty  times. 


FIG   1G2.  —Acorn-shell  barnacles  on  a  sand  dollar. 


140 


ARTHROPODA 


pearance   as  to  lack  all  features   characteristic   of   the 
class. 

The  barnades  found  only  in  salt  water  show  how  organs 

originally  intended  for 
one  purpose  may  be 
adapted  to  another.  The 
acorn-shell  barnacle  (Bal- 
anus  balanoides)  lives  in 
calcareous  shells  at- 
tached to  the  bottoms 
of  ships,  wharves,  or 
other  objects  in  the 
water.  The  legs  no  longer 
needed  for  locomotion, 
as  in  its  ancestors,  are 
extended  through  the 
open  shell  to  secure  food. 
On  account  of  disuse  the 
eyes  have  been  lost. 
The  goose  barnacle  (Lepas 

anatifera)  is  often  found  attached  to  floating  objects  by 
a  stem  two  or  three  inches  in  length.     Between  the  two 
pairs  of  calcareous  plates 
protecting  the  body  are 
thrust  appendages,  form- 
erly   used    as    legs,    to 
catch  food. 

The  terrestrial  crusta- 
ceans number  but  a  few 
species.  The  common 
ones  known  as  pill  bugs, 


FIG.  163.  —  Goose  barnacles  with  tb e  right  shell 
removed  from  the  one  on  the  left.    Natural 


FIG.  164. —Sow  bug  (Oniscus  asellus).     After 
Paulmier. 


CliUSTACEA  141 

sow  bugs,  or  wood  lice  abound  everywhere  under  logs  and 
stones  during  most  of  the  year.  They  are  about  a  half 
inch  long  and  have  a  convex  grayish  dorsal  surface.  They 
feed  on  decaying  vegetable  matter.  Respiration  is  effected 
by  gills  instead  of  by  lungs  or  trachea  characteristic  of 
most  land  forms.  The  inner  terminal  divisions  of  the 
abdominal  legs,  which  are  covered  and  kept  moist  by  the 
outer  division,  are  the  gills. 

Crustaceans  are  remarkable  for  their  perfect  adaptation 
to  widely  different 
conditions  of  life. 
They  dwell  in  fresh 
water,  in  the  sea, 
on  land,  and  as 
parasites.  In  the 
Mammoth  Cave  of 
Kentucky  are  blind 

FIG. 165. —  Photograph  of  the  shrimp.    Natural  size. 

crayfish     which 

show  by  certain  features  that  they  are  undoubtedly  de- 
scended from  the  forms  outside  of  the  cave  enjoying  perfect 
sight.  Some  species  live  in  the  ocean  at  a  depth  of  nearly 
four  miles.  While  most  crustaceans  are  solitary,  some 
like  the  shrimp  much  used  for  food  occur  in  vast  shoals  in 
the  ocean. 


PART  II 

THE  ANARTHROPODA :   INVERTEBRATES 
WITHOUT   JOINTED   LEGS 

10.   MOLLUSCA 

THE  members  of  this  phylum  differ  from  the  preceding 
in  not  having  segmented  bodies  or  jointed  feet.  Most  of 
the  twenty  thousand  species  are  included  in  the  three 
important  classes,  —  Pelecypoda,  Gastropoda,  and  Cepha- 
lopoda. 

Pelecypoda:  Bivalved  Shellfish 

The  name  bivalve  is  derived  from  the  two  shells  which 
hinged  together  form  the  protecting  case  for  the  soft- 
bodied  animal  within.  All  bivalves  are  aquatic.  Certain 
species  form  a  leading  item  of  food  in  many  parts  of  the 
world. 

The  soft-shelled  clam  (My a  arenaria),  abundant  north  of 
Cape  Cod,  occurs  in  large  numbers  in  the  mud  flats,  from 
which  they  are  dug  at  low  tide.  They  usually  lie  in  the 
mud  at  a  depth  of  from  two  inches  to  a  foot,  and  have  a 
very  long  siphon  consisting  of  two  tubes,  of  which  the 
ventral  one  is  used  for  taking  in  water  and  food,  while  the 
excretory  products  pass  out  through  the  dorsal  one. 

The  hard-shelled  clam  (Venus  mercenaria),  or  quahog,  is 
the  common  edible  species  south  of  Cape  Cod. 

142 


MOLLUSCA 


143 


The  fresh  water  clams,  Anodonta  and  Unio,  often  called 
mussels,  are  present  in  large  numbers  in  some  fresh  water 
streams  and  lakes.  The  shell  of  the  Unio  is  smaller  and 
thinner  than  that  of  Anodonta.  The  sexes  are  separate, 
but  the  male  re- 
sembles the  female 
so  closely  that  a 
microscopic  exam- 
ination of  the  re- 
productive glands 
is  necessary  to  dis- 
tinguish one  from 

the  Other.  FIG.  16o.  —  Sof t-shelled  clam  with  a  piece  cut  out  of 

The  ejrprs  of  clams       the  end  of  the  sipllon  to  snow  botl1  tubes.  Photo- 

°°  graph  natural  size. 

are  hatched  within 

the  shell  of  the  mother,  and  in  a  few  months  the  young 
pass  out  into  the  water  and  attach  themselves  to  fishes 
by  a  pair  of  sharp  projections 
on  the  ventral  margins  of  the 
shell.  Here  they  lead  a  para- 
sitic life,  absorbing  juices  from 
the  body  of  the  fish  for  some 
weeks  and  pass  through  a 
metamorphosis,  after  which 
they  drop  to  the  bottom  and 
feed  on  small  crustaceans  and 
other  aquatic  organisms.  Most 
clams  move  about  from  time 
to  time  by  means  of  a  single  ventral  projection,  the  foot, 
which  is  protruded  between  the  open  valves. 
The  oyster  (Ostrea  virginiana),  so  highly  prized  for  food, 


FIG.    167.  —  Hard-shelled     clam. 
Photograph  half  natural  size. 


144 


ANARTHROPODA 


FIG.  168.  — Oyster  of  t 
(Ostrea  virginiana). 
half  natural  size. 


Photograph  one 


differs  from  the  clams  in  having  no  siphon  and  a  foot  so 
rudimentary  as  to  be  unable  to  move.  The  oystermen  are 
therefore  accustomed  to  plant  the  young  in  shallow  water 
where  they  remain  three  or  four  years  to  mature.  Our 

Atlantic  coast  furnishes 
twenty-five  millions  of  dol- 
lars' worth  of  oysters  an- 
nually. The  Japan  oysters 
are  the  largest,  some  species 
attaining  a  length  of  three 
feet. 

The  pearl  oysters  (Melea- 
grina),  along   the   Persian 

Quj£  and   coagts  Qf   Ceylol^ 

are  the  source  of  most 
pearls,  but  some  pearls  have  been  found  in  the  fresh  water 
clams  and  oysters  of  our  own  country.  Pearls  are  depos- 
its of  nacre  formed  around  foreign  bodies  by  the  mantle, 
and  are  of  the 
same  composition 
as  the  inner  lining 
of  the  shell  so 
much  valued  as 
the  mother  of 
pearl.  The  ship- 
worm  (Teredo 
navalis)  is  a  pecu- 
liar bivalve,  causing  much  damage  by  boring  into  ships 
and  piles  supporting  the  wharves  along  the  ocean. 

Anatomy  of  the  Fresh  Water  Mussel.  —  Any  clam  may 
be  used  for  dissection,  but  the  following  description  applies 


FIG.  169.  —  Photograph  of  the  shipworm  slightly  en- 
larged. 


MOLLUSCA 


145 


particularly  to  the  fresh  water  mussel.  A  horny  or  elastic 
ligament  unites  the  two  valves  on  the  dorsal  aspect  and 
tends  to  open  the  shell  along  the  ventral  margin.  The 
concentric  parallel  ridges  on  the  outside  of  the  shell  repre- 
sent successive  additions  of  lime  and  are  called  lines  of 
growth.  The  eleva- 
tion near  the  hinge 
is  the  wnbo.  To 
open  the  shell  place 
it  in  boiling  water 
a  minute  or  two  and 
then  slip  the  knife 
between  the  two 
slightly  open  valves 
and  loosen  the  ad- 
ductor muscles  from 
one  side  of  the  shell. 
The  line  within 
the  valve  concentric 
with  the  ventral 
margin  and  connect- 
ing the  two  muscle 
scars  is  the  pallial  line  along  which  a  membrane,  the 
mantle,  is  attached.  The  two  mantles  covering  the  body  of 
the  mussel  are  almost  as  large  as  the  valves  to  which  they 
adhere  closely.  By  removing  the  left  mantle  and  immers- 
ing the  specimen  in  a  pan  of  water  the  relations  of  the  soft 
parts  may  be  made  out.  The  firm  conical  mass  projecting 
ventral  and  anteriorly  is  the  foot.  The  gills  are  the  two 
thin  membranes  on  either  side  of  the  body  just  within  the 
mantle.  They  are  covered  with  ciliated  cells,  whose  pur- 


FIG.  170. — Wood  injured  by  the  ship  worm. 


146 


ANARTHROPODA 


FIG.  171.  — A  freshwater  mussel  with  the  right  valve  mantle  and  gills  and  some 
tissue  at  the  base  of  the  foot  removed  ;  a,  anterior  adductor  muscle  ;  au,  auricle 
of  the  heart ;  ft,  foot ;  g,  reproductive  gland  ;  gl,  gill ;  i,  intestine  ;  k,  kidney  ; 
m,  mantle ;  n,  nerve  ganglia  connected  by  nerve  cords  o  ;  p,  posterior  adductor ; 
pi,  labial  palps  ;  si,  siphon  ;  v,  ventricle.  The  dark  lines  on  the  mantle  and 
foot  are  blood  vessels. 

pose  it  is  to  cause  the  water  to  flow  in  and  out  through 
the  siphons,  thereby  bringing  in  food  and  oxygen.  By 
detaching  a  minute  portion  of  the  gill  of  a  live  mussel 
and  mounting  it  in  a  drop  of  water  on  a  glass  slip  and 
examining  with  the  microscope  the  cilia  (hairlike  pro- 
cesses) may  be  seen  in  motion. 

The  heart,  consisting  of  two  auricles  and  a  ventricle,  is 
seen  by  removing  the  dorsal  portion  of  the  mantle.  In  a 
live  mussel  opened,  the  heart  can  be  noticed  beating,  as 
the  milky  blood  passes  from  the  auricles  to  the  ventricle 
and  thence  through  the  pedal  artery  to  the  foot  and  body. 
It  then  goes  to  the  gills  where  carbon  dioxide  is  given  off 
and  oxygen  received  before  it  is  returned  to  the  heart. 


MOLLUSCA  147 

The  digestive  system  is  well  defined.  Near  the  anterior 
adductor  muscle  between  the  two  pairs  of  triangular  flaps, 
called  labial  palps,  :'s  the  mouth  opening  into  a  short  esopha- 
gus leading  into  the  stomach  surrounded  by  a  dark  tender 
mass  of  tissue,  the  liver,  from  which  ducts  empty  into  the 
stomach.  The  intestine  after  leaving  the  stomach  makes 
a  turn  on  itself  in  addition  to  several  bends,  and  terminates 
dorsal  of  the  posterior  adductor  muscle  in  the  exhalant 
siphon. 

The  nervous  system  is  difficult  to  demonstrate.  It  con- 
sists of  three  pairs  of  ganglia  or  bunches  of  nerve  cells 
connected  by  nerve  cords.  The  visceral  ganglia  he  on  the 
under  side  of  the  posterior  adductor  muscle.  From  these 
a  pair  of  threadlike  nerves  extend  forward  to  the  cerebral 
ganglia  at  the  base  of  the  labial  palps  and  behind  the  an- 
terior adductor  muscle.  A  circular  nerve  cord  joining 
these  two  ganglia  surrounds  the  mouth  and  from  each  a 
nerve  cord  leads  to  the  pedal  ganglion  near  the  center  of 
the  foot. 

Gastropoda:  Snails  and  Slugs 

The  univalve  mollusks  are  unsymmetrical  and  have  but 
one  shell  which  is  often  in  the  form  of  a  spiral.  The  pond 
snail  (Limnea),  abundant  in  ditches  and  stagnant  ponds, 
has  a  right-handed  shell,  i.e.,  starting  from  the  apex  the 
coil  turns  toward  the  right.  Physa,  the  other  pond  snail, 
has  a  left-handed  shell.  The  eggs  of  pond  snails  appear  as 
minute  white  spots  in  a  mass  of  transparent  albumen. 
During  the  summer  months  they  are  easily  found  adhering 
to  boards,  stones,  and  other  objects  in  the  quiet  waters. 


148 


ANARTHROPODA 


FIG.  173.— Forest  snail  show- 
ing the  two  tentacles  with 
an  eye  on  the  end  of  each. 
Photograph  from  life. 


FIG.  172.  —  Pond  snail  and  two  of  its  egg 
masses.  The  one  on  the  right  is  entirely 
withdrawn  in  its  shell.  Photograph  from 
life  natural  size. 


FIG.  174.  —  Photograph  of  the  big  slug  one  half  natural  size. 


MOLLUSCA 


149 


Examination  of  the  young  while  still  in  the  egg  mass  will 
show  the  beating  of  the  heart. 

Planorbis,  another  aquatic  snail,  is  distinguished  by 
having  all  its  whorls  in  the  same  plane.  The  forest  snail 
(Helix  alboldbris)  and  the  big  slug  (Limax  maximus)  are 
terrestrial.  The  slugs  are  characterized  by  the  absence 
of  an  external  shell  and  in  its  stead  a  plate-like  shell  buried 
in  the  mantle  on  the  back.  Slugs  and  snails  breathe  by 
means  of  lungs,  the  opening  to  which  is  a  round  hole  at 
the  edge  of  the  mantle.  Slugs  are  destructive  to  garden 
plants,  a  common  offender  being  the 
small  dark  brown  one  hiding  by  day 
under  boards  arid  logs. 

Cephalopoda:  Squids,  Cuttlefish,  etc. 

The  members  of  this  class  are  so 
named  because  a  portion  of  the  foot  is 
fused  with  the  head.  Around  the  mouth 
are  several  tentacles  or  arms  provided 
with  suckers,  serving  as  powerful  organs 
in  seizing  prey.  In  the  common  squid 
(Loligo  pealii),  the  lower  portion  of  the 
foot  forms  a  tube  through  which  the 
water  contained  in  the  mantle  cavity 
may  be  violently  expelled  and  the  ani- 
mal thus  propelled  through  the  water. 
Into  this  funnel  opens  the  duct  of  the. 
ink  sac  by  which  the  squid  and  cuttlefish  color  the  water 
in  order  to  escape  from  their  enemies.  The  sense  of  sight 
is  well  developed  in  the  cephalopods,  a  large  eye  being 


FIG.  175.  —  The  squid. 
One  fourth,  natural 
size. 


150  ANARTHROPODA 

located  on  either  side  of  the  head.  In  the  squids  and  cuttle- 
fish the  shell  is  rudimentary  and  is  buried  within  the 
mantle,  while  in  the  pearly  nautilus  (Nautilus  pompilius) 
it  is  in  the  form  of  a  spiral  divided  into  chambers,  the  larg- 
est and  outer  of  which  is  alone  occupied  by  the  animal. 
As  soon  as  the  body  becomes 
too  small  for  one  chamber  it 
moves  forward,  constructing  a 
partition  behind  it.  This  is  the 
creature  which  inspired  the  cele- 
brated poem,  "The  Chambered 
Nautilus,"  by  Holmes. 

The  cephalopods  are  of  little 
economic  importance.   The  cut- 
.  176. -Pearly  nautilus  ™th     tlefish  supply  sepia  for  the  artist 

half  the  shell  removed. 

and  are  of  some  use  for  food. 
Squid  are  used  for  cod  bait  along  the  New  England  shore. 

ii.   VERMES 

The  worms  form  a  group  of  animals  not  easily  defined 
because  of  their  great  variation  in  structure  and  habits; 
therefore,  modern  zoologists  have  separated  them  into  sev- 
eral subkingdoms,  of  which  the  three  most  important  are 
Annulata,  Nemathelminthes,  and  Platyhelminthes. 

Annulata  or  Segmented  Worms 

This  phylum  is  widely  represented  by  leeches  and  earth- 
worms. As  the  habits  of  the  two  groups  are  quite  different, 
each  will  be  described  separately. 

Leeches.  —  These  are  often  called  bloodsuckers,  owing  to 


VEEMES  151 

their  habit  of  fastening  themselves  to  the  skin  of  man 
or  any  of  the  lower  animals  and  sucking  their  blood.  They 
are  Usually  found  in  moist  places  only,  often  being  aquatic. 


FIG.  177.  — Photograph  of  the  medicinal  leech.    Natural  size. 

The  medicinal  leech  (Hirudo  medicinalis)  was  used  fifty 
years  ago  for  blood-letting  when  the  fallacious  idea  pre- 


Fi«.  178.  —  The  large  water  leech  just  after  a  full  meal.    Ventral  view  showing  both 
suckers,  head  at  the  left.    Photograph  natural  size. 

vailed  that  people  could  be  cured  of  sickness  by  letting 
out  the  bad  blood.  After  the  leech  fastens  itself  to  the 
skin  by  its  suckers  the  toothed  jaws  quickly  rasp  a  hole 


152  ANARTHROPODA 

through  to  the  superficial  blood  vessels  and  in  an  hour  the 
hungry  creature  will  be  distended  to  triple  its  former  size. 
The  alimentary  canal  has  several  pouches  along  either  side 
to  increase  its  capacity.  A  full  meal  lasts  the  animal  one 
year. 

Tn  some  parts  of  the  tropics  such  as  India  and  Ceylon, 
there  are  land  leeches  about  an  inch  long  in  the  meadows 
and  woods  capable  of  scenting  their  prey  at  some  distance, 


FIG.  179.  —  Night  walker  ;  c,  clitellum  ;  TO,  mouth  ;  n,  opening  of  reproductive  glands. 
Photograph  natural  size. 

and  are  quick  in  their  movements,  so  that  a  person  brushing 
through  the  jungle  often  becomes  covered  with  them.  The 
largest  leech  is  an  American  species,  Macrobdella  valdiviana, 
which  attains  a  length  of  more  than  two  feet. 

Earthworms.  —  These  are  often  called  rain  worms  or 
angleworms.  There  are  a  dozen  or  more  species  in  tliis 
country,  but  for  study  the  night  walker  (Lumbricus  agri- 
cola)  is  best  on  account  of  its  large  size.  It  may  be  recog- 
nized by  its  flattened  posterior  end.  It  lives  in  rich  garden 
soil  and  near  manure  piles.  In  dry  weather  the  holes  may 
extend  to  a  depth  of  six  feet.  Specimens  may  often  be 


VERMES  153 

caught  by  seeking  them  with  a  lantern  at  night  when  they 
roam  about.  They  can  easily  be  kept  for  months  in  a  box 
of  rich  earth  occasionally  moistened  and  supplied  with 
decaying  leaves.  A  wire  netting  should  be  tacked  over  the 
top.  In  order  to  kill  them  properly  for  dissection,  they 
should  be  placed  in  a  jar  or  dish  a  foot  in  diameter  and  cov- 
ered with  water  to  which  thirty  cubic  centimeters  (one 
ounce)  of  alcohol  is  to  be  added  every  forty  or  fifty  minutes 


FlG.  180.  —  Forepart  of  an  earthworm  with  the  left  body-wall  removed  ;  a,  dorsal 
blood  vessel;   6,  brain  ;  c,  crop  ;  d,  opening  of  the  male  reproductive  organs  ; 
g,  gizzard  ;  i,  intestine  ;  k,  kidney  ;  m,  mouth  ;  «,  one  of  the  ganglia  of  the  nerve 
cord  ;  oe,  esophagus  ;  p,  pharynx  ;  r,  receptacles  for  sperm  cells  ;  ov,  ovary  ;  ovd,  ' 
duct  from  ovary  ;  v,  ventral  blood  vessel.    Drawing  by  W.  H.  Reese. 

until  they  become  unconscious.     They  are  then  best  pre- 
served in  seventy  per  cent  alcohol. 

Each  of  the  segments  or  somites  numbering  about  one 
hundred  and  fifty  bears  four  pairs  of  short  bristles  (setce) 
by  means  of  which  the  worm  holds  itself  so  firmly  in  the 
burrow  when  one  attempts  to  dislodge  it.  The  swollen 
band  between  the  thirtieth  and  fortieth  somites  is  the 
clitellum,  from  which  exudes  a  sticky  substance  used  to 
construct  the  egg  band.  This  encircling  band  after  being 
hardened  by  the  air  is  worked  forward  and  as  it  passes  the 
fourteenth  or  fifteenth  segments  receives  the  eggs  there 
extruded  by  two  minute  apertures  not  visible  to  the  naked 


154  ANARTHROPODA 

eye.  Between  the  ninth  and  eleventh  somites  are  two 
pairs  of  openings  from  which  sperm  cells  enter  the  band 
and  render  the  several  eggs  fertile.  As  the  band  slips  off 
the  head  it  is  changed  into  a  closed  capsule  within  which 
only  one  worm  develops,  the  others  being  devoured  by 
the  sole  survivor. 

For  dissection,  a  worm  over  five  inches  long  should  be 
pinned  ventral  side  down  in  a  pan  of  water  and  a  slit  made 
with  the  scissors  through  the  body  wall  in  the  anterior 
half  along  the  mid-dorsal  line.  Pin  down  the  body  walls 
on  either  side  and  note  the  parts  as  shown  in  the  figure. 
The  blood  runs  forward  in  the  dorsal  vessel  and  backward 
in  the  ventral  one.  No  true  heart  is  present,  but  the  five 
pairs  of  aortic  arches  are  contractile.  The  paired  nephridia 
in  each  somite  are  the  kidneys,  which  conduct  the  waste 
matter  outside  of  the  body.  The  worm  has  no  tracheal 
tubes,  gills,  or  lungs,  but  receives  oxygen  into  the  blood 
and  casts  out  the  carbon  dioxide  by  means  of  the  small 
vessels  ramifying  near  the  surface. 

Earthworms  feed  on  decayed  leaves  and  other  vegetable 
matter.  They  are  of  much  service  in  keeping  the  soil 
loose  and  permitting  the  water  and  air  to  penetrate  to  the 
roots  of  plants  by  means  of  their  burrows.  They  also 
make  good  food  for  birds.  Their  power  of  regeneration 
after  injury  is  remarkable.  If  one  be  cut  in  two  near  the 
middle  each  half  will  often  develop  into  a  complete  worm. 
The  power  to  regenerate  lost  parts  is  much  greater  in  the 
lower  animals  than  in  the  higher  ones.  A  tadpole  may 
regenerate  a  lost  leg  but  not  a  half  or  even  a  fourth  of  its 
body,  while  a  mammal  can  not  reproduce  even  a  fourth  of 
a  finger  or  toe  removed, 


VEKMES 


155 


Nemathelminthes  or  Threadworms 

The  round  worms  differ  from  the  Annulata  in  not  show- 
ing any  external  evidence  of  segmentation.  Most  of  the 
species  live  as  parasites  during  part  or  all  their  lives.  As- 
caris  is  a  genus  containing  several  species  which  are  often 
present  in  the  in- 
testines of  mam- 
mals, and  one  spe- 
cies is  common  in 
the  lungs  of  the 
frog.  Trichina,  a 
microscopic  round 
worm  causing  the 
condition  known 
as  measly  pork,  is 
a  dangerous  para- 
site to  man.  He 
becomes  infected 
by  eating  affected 
pork  not  well 
cooked.  In  1892, 
the  United  States  Department  of  Agriculture  found  over 
seventeen  thousand  carcasses  of  hogs  containing  Trichina?. 
A  fuller  discussion  of  parasitic  worms  is  given  in  the  chap- 
ter on  parasites. 

The  vinegar  eel  (Anguillula)  is  a  free  living  worm  often 
present  in  good  cider  vinegar.  It  is  just  large  enough  to  be 
recognized  by  the  naked  eye,  and  if  a  little  vial  containing 
some  vinegar  be  looked  at  toward  the  light  as  many  as  five 
hundred  may  be  seen  squirming  vigorously.  They  are 


FIG.  181.  —  Ascaris  lumbricoides  :  a  parasite  often 
present  in  the  intestine  of  children.  Photograph, 
natural  size. 


156 


ANARTHROPODA 


FlG.  182.  — Three  encysted  Trichinae  in  human  flesh.    Photograph  enlarged  sixty 
diameters. 

harmless  to  man.  A  species  of  Anguillula  is  also  common 
in  stagnant  ponds  and  ditches,  and  may  be  found  by  ex- 
amining under  the  low  power  of  the  microscope  a  drop 
of  water  scraped  from  decaying  wood  or  leaves  taken  from 
foul  water. 

Horse-hair  worms  of  which  Gordius  aquations  is  the  most 
common  occur  in  streams,  ponds,  and  watering  troughs. 
They  do  not  originate  from  a  horse  hair,  as  is  popularly  sup- 
posed. They  are  from  five  to  ten  inches  long  and  as  thick 
as  a  pin.  The  eggs  are  either  laid  in  the  damp  earth  or 
water.  In  the  latter  case  the  young  socn  after  hatching 
bore  into  the  larva  of  some  aquatic  insect  which  is  later 
eaten  by  a  fish.  The  young  hair  worm  no  larger  than  a 


VERMES 


157 


pin  head  works  its 
way  through  the 
walls  of  the  fish's 
intestine  to  the 
muscles,  remains 
several  months 
quiescent  until 
spring,  when  it 
again  enters  the 
i  n  t  e  s  t  i  n  e  and 
passes  out  into  the 
water.  Its  length 
at  this  time  is 
about  an  inch. 

In  a  few  weeks  it  reaches  full  size.  The  young  of  those 
species  laying  eggs  in  the  damp  earth  bore  into  caterpillars, 
grasshoppers,  locusts,  and  beetles.  During  the  months 
of  August,  September,  and  October  hair  worms  may  some- 
times be  found  in  the  locusts  by  pulling  open  the  abdom- 
inal cavity  with  forceps  or  needles. 


FIG.  183.  — Horse-hair  snake.     Photograph  twice 
natural  size. 


Platyhelminthes  or  Flatworms 

The  flatworms  are  remarkable  for  their  variation  in 
size.  Some  of  them  living  parasitic  on  the  gills  of  fish 
and  the  king  crab  are  only  one  or  two  millimeters  long, 
while  the  tapeworms  parasitic  in  man  reach  a  length  of 
fifty  feet.  Many  members  of  this  phylum  are  parasites 
and  all  have  soft  bodies  usually  much  flattened  dorso- 
ventrally.  There  is  no  body  cavity  (ccelome)  surrounding 


158  ANARTHROPODA 

the  internal  organs,  this  space  being  filled  up  with  a  kind 
of  connective  tissue  called  parenchyma. 

Tapeworms.  —  These  are  so  named  because  they  resem- 
ble a  piece  of  tape.     All  are  parasites  and  dwell  within 


FIG.  184.— Human  tapeworm  fourteen  feet  in  length;  ht  head.    Photograph  three 
fourths  natural  size. 

various  species  of  vertebrates  from  fish  to  man.  The 
life  history  of  Tcenia  saginata,  a  human  parasite,  is  typical 
of  the  group.  In  the  adult  state  it  dwells  only  in  the 
intestine  of  man  and  is  usually  from  ten  to  fifty  feet  in 
length.  Its  head  known  as  the  scolex  is  armed  with  four 


VERMES 


159 


suckers  enabling  it  to  hold  fast  in  the  mucous  coat  of  the 
canal,  while  its  body,  called  strobila,  lies  free  in  the  intestine. 
The  segments  of  the  body,  narrow  and  short  near  the  head, 
increase  in  size  posteriorly  and  may  number  as  many  as 
one  thousand.  They  are  known  as  proglottides.  It  has 
no  alimentary  canal  and  no  blood  system,  the  nourish- 
ment being  absorbed  through  the  body  wall.  The  nervous 
system  consists  of  two  small  ganglia  in  the  head  and  a 
nerve  cord  extending  from  them  along  each  side  of  the 
body.  Each  of  the  segments  in  the  posterior  half  of  the 
adult  worm  contains  both  male  and  female  organs  of 
reproduction  and 
each  segment 
near  the  end  has 
more  than  a  thou- 
sand mature  eggs. 
From  time  to 
time  a  segment 
is  broken  off  and 
passes  to  the  ex- 
terior where  if 
through  water  or 
otherwise  the  eggs 
within  it  reach 
the  alimentary 
canal  of  the  cow 
further  develop- 
ment ensues. 

The  young  migrate  from  the  digestive  tract  of  the  cow  to 
the  muscles  and  form  a  cyst  or  sac  in  which  stage  it  is 
known  as  a  bladder  worm  or  cysticercus.  This  is  the  larval 


FIG.  185.  — A  piece  of  pork  containing  several  cysti- 
cerci  (larvae)  of  a  human  tapeworm  (Tsenia  soliurri). 
Photograph  natural  size. 


160 


ANARTHROPODA 


state,  and  no  further  growth  occurs  until  the  meat  is 
eaten  by  man  in  whom  the  larva  transforms  into  the 
tape  form.  The  poisonous  excretions  given  off  by  the 
worm  cause  nausea,  headache,  and  dizziness  in  the  host. 

The  larval  stage  of  the  tapeworm  of  the  dog  is  found 
in  the  rabbit,  while  the  early  stage  of  the  cat's  tapeworm 
occurs  in  the  mouse.  It  is  therefore  evident  that  the 
completion  of  the  life  cycle  in  these  parasites  requires  two 
hosts. 

Fresh  Water  Flatworms.  —  These  are  common  in  most 
ponds  and  streams.  They  vary  in  size  from  minute 

specks  to  forms 
more  than  a  half 
inch  in  length. 
The  whitish  or 
grayish  color  to- 
gether with  their 
slow  gliding  move- 
ments over  the 
surface  of  water 
plants  and  the 
under  sides  of  stones  and  sticks  are  the  features  by  which 
they  may  be  recognized.  They  move  largely  by  means 
of  the  cilia  over  the  surface.  A  good  plan  for  secur- 
ing them  is  to  place  in  a  jar  of  water  some  sticks  and 
leaves  taken  from  several  quiet  pools.  The  following  day 
they  may  be  seen  on  the  side  of  the  vessel.  In  many 
forms  the  mouth  is  in  the  middle  of  the  under  side  and  the 
alimentary  canal  has  a  forward  and  two  backward  exten- 
sions with  numerous  lateral  branches.  This  group  has  the 
power  of  regeneration  to  such  a  degree  that  if  an  individual 


FIG.  18G.  —  Planaria ;  a  common  aquatic  flatworm. 
The  two  minute  dots  in  the  head  are  the  eyes,  and 
the  black  much  branched  structure  is  the  alimen- 
tary canal.  Photograph  enlarged  four  diameters. 


ECHINODERMATA  161 

be  cut  into  several  pieces  each  one  will  grow  into  a  com- 
plete worm. 

The  largest  of  the  flatworms  are  marine  and  belong  to 
the  group  Nemertini.  Some  of  these  reach  a  length  of 
nearly  one  hundred  feet.  The  common  form  found  along 
the  Atlantic  coast  is  Cerebratulus,  which  has  a  flat,  cream- 
colored  body  two  or  three  feet  long.  It  inhabits  the  mud 
and  sand  at  the  water's  edge  where  it  may  be  dug  out  during 
low  tide. 

The  Rotifers  are  interesting  microscopic  worms  present 
in  stagnant  water.  They  belong  to  the  subkingdom  of 
Trochelminthes.  Upon  the  head  are  two  circles  of  cilia 
so  vibrating  to  draw  in  food  as  to  resemble  the  rotation 
of  a  wheel.  In  early  summer  they  are  parthenogenetic, 
i.e.,  young  are  produced  from  eggs  which  have  not  been 
made  fertile  by  the  entrance  into  them  of  the  sperms  (re- 
productive cells  of  the  male). 


12.   ECHINODERMATA 

This  phylum  derives  its  name  from  the  rough  or  spiny 
skin  common  to  many  of  the  species,  such  as  the  starfish 
and  the  sea  urchins.  All  of  the  members  of  this  group 
dwell  in  salt  water. 

The  Starfish  (Asterias  vulgaris) .  —  Of  the  several  species 
of  starfish  living  at  depths  of  from  one  to  three  hundred 
feet,  the  larger  forms  should  be  chosen  for  study.  They 
are  numerous  in  the  vicinity  of  oyster  beds  as  they  prey 
on  these  shellfish,  causing  great  loss  to  the  oyster  industry. 

The  normal  starfish  has  five  arms  of  equal  length,  but 


162  ANARTHROPODA 

specimens  are  often  found  with  as  few  as  one  or  two  arms 
full  length  and  the  others  appearing  as  mere  buds.  This 
is  due  to  the  fact  that  the  arms  have  been  broken  off  and 
are  just  beginning  to  grow.  If  all  five  arms  are  cut  off 
they  will  be  reproduced.  The  skeleton  of  the  animal  con- 


PlO.  187.— Dorsal  or  top  surface  of  the  starfish  ;  m,  madreporic  plate.    Photo- 
graph half  natural  size. 

sists  of  flat,  irregular  calcareous  plates  imbedded  edge  to 
edge  in  a  leathery  skin  containing  numerous  pores  through 
which  fingerlike  processes  project  and  function  as  gills. 
The  madreporic  plate  forms  a  sieve  through  which  the  water 
passes  into  the  stone  canal  leading  down  to  the  ambulacral 
or  water-vascular  system.  The  latter  consists  of  a  vessel 
encircling  the  mouth  and  sending  a  branch  into  each  arm 
to  connect  with  the  feet.  The  numerous  feet  are  visible 


ECHINODERMATA  163 

in  the  five  ambulacral  grooves  on  the  ventral  sides  of  the 
arms.  The  mouth  is  the  circular  opening  in  the  center 
of  the  ventral  surface. 

To  study  the  internal  organs  place  the  specimen  in  a 
pan  of  water  deep  enough  to  cover  it,  and  with  the  scissors 


FIG.  188.  — Ventral  or  under  surface  of  the  starfish.  Black  circle  in  the  middle 
is  the  mouth  from  which  radiate  the  five  ambulacral  grooves,  each  filled  with 
about  a  hundred  feet.  Photograph  half  natural  size. 

remove  the  skin  from  nearly  half  the  dorsal  surface  cutting 
alongside  the  madreporic  plate  remaining  in  place.  The 
saclike  stomach  occupies  the  body  just  beneath  the  skin 
and  from  it  bifurcated  processes,  the  pyloric  cceca,  extend 
more  than  half  way  to  the  ends  of  the  arms.  By  slightly 
raising  the  skin  bearing  the  madreporic  plate,  the  slender 
stone  canal  may  be  seen  leading  to  the  ring  around  the 


164 


ANARTHROPODA 


FIG.  189.  —  Vertical  section  of  one  arm  of  a  starfish  ;  a,  anus  ;  6,  ampulla  ;  c,  car- 
diac stomach  ;  ct,  connection  of  pyloric  caeca  with  stomach  ;  d,  stone  canal ;  i, 
radial  ambulacral  vessel ;  ft,  feet ;  m,  mouth ;  n,  cut  end  of  nerve  ring  sur- 
rounding the  mouth ;  py,  pyloric  caeca ;  r,  respiratory  organ  ;  rp,  ovary  ;  st, 
madreporic  plate ;  stct  stomach. 

mouth.    The  removal  of  the  pyloric  caeca  makes  visible 
along  the  floor  of  the  arm  two  rows  of  little  bladders, 


FlG.  IW.  —  Strongylocentrotus:  the  green  urchin  on  the  left,  and  Arbacia  the  black 
urchin  on  the  right.  The  green  urchin  seen  from  the  ventral  side  shows  white 
teeth  filling  the  mouth  and  numerous  feet  among  the  spines.  Photograph  half 
natural  size. 

ampullce,  which  are  usually  in  a  collapsed  condition.    These 
receive  the  water  from  the  radial  ambulacral  vessel  extend- 


ECHINODERMATA  165 

ing  through  each  arm,  and  discharge  it  into  the  feet  by 
means  of  which  they  are  extended,  then  sucked  fast  to  an 
object,  and  contracted  to  pull  the  animal  along.  The  star- 
fish has  no  heart,  but  a  circular  blood  vessel  surrounds  the 
mouth  and  gives  off  a  branch  to  each  arm. 

The  nervous  system  consists  of  a  ring  around  the  mouth 
and  five  radial  nerves  supplying  the  arms.    This  system 


FIG.  191.  — Sea  cucumber  (Pentactafrondosa).    Photograph  natural  size. 

is  easily  seen  on  the  ventral  surface  by  separating  the  two 
rows  of  feet  in  each  ambulacral  groove.  The  male  can  be 
distinguished  from  the  female  only  by  a  microscopic  exami- 
nation of  the  reproductive  glands,  of  which  there  are  five 
pairs  lying  at  the  junction  of  the  arms  with  the  body.  Each 
gland  with  its  tip  toward  the  point  of  the  arm  may  be  a 
half  inch  long,  or  if  ripe  two  or  three  inches  long. 

Arbacia  of  dark  color  and  Strongylocenlrotus  of  a  green- 
ish hue  are  common  representatives  of  the  sea  urchins 
(Echinoidce)  which  are  characterized  by  the  presence  of 


166  ANARTHROPODA 

pronounced  spines  and  usually  a  globular  or  disk-shaped 
body  without  arms.    The  true  urchins  are  common  along 
muddy  coasts,  and  the  sand  dollars  flat  and  with  short, 
weak  spines  are  most  prevalent  along  sandy  shores. 
The  sea  cucumbers  (Hokthuroidea)  have  elongated  cylin- 


FlG.  192. —A  brittle  star  (Ophiopholis  bellis).     Photograph  natural  size. 

drical  bodies  with  a  circle  of  branched  tentacles  about  the 
mouth,  and  from  it  five  rows  of  feet  extend  posteriorly. 
They  are  found  in  the  mud  at  the  water's  edge  during  low 
tide. 

The  brittle  stars  (Ophiuroidea)  have  five  arms  much  more 
slender  than  those  of  the  starfish  and  no  ambulacral  grooves 
are  present.  The  crinoids  (Crincridea)  including  the  feather 


ECHINODERMATA 


167 


stars  and  sea  lilies  differ  from  most 
animals  in  being  attached  to  some 
object  by  a  stalk.  They  usually 
live  at  considerable  depth  in  the 
sea.  Fossil  remains  show  that  these 
animals  were  very  abundant  several 
millions  of  years  ago  in  the-  Silurian 
period.  To-day  but  few  species  exist. 
The  Echinodermata  are  lower  in  the 
animal  scale  than  most  of  the  preceding 
phyla,  as  they  have  no  heart  and  very 
simple  nervous  and  excretory  systems. 
The  senses  of  sight  and  hearing  seem  to  be 
entirely  wanting,  and  the  sense  of  smell 
is  very  little  developed.  All  the  species 
live  in  the  same  environment  and  present 
the  same  characteristic  radiate  structure. 


FIG.  193.  —  Crinoid  show- 
ing the  stem  with  which 
it  is  attached. 


13.  CCELENTERATA  AND   PORIFERA 

The  two  groups  of  animals  discussed  in  this  chapter  were 
formerly  placed  in  the  same  phylum  because  they  are  so 

much  alike  in  hab- 
its and  structure. 
The  stinging  or 
nettle  cells  pos- 
sessed by  the  Coelen- 
terata  and  wanting 
in  the  Porifera 
separate  clearly 

.  194.  — Diagrammatic  cross  section  of  the  body  of  a 
coelenterate  A,  and  that  of  a  worm  or  insect  B.  the  tWO  groups. 


168  ANARTHROPODA 


Ccelenterata :  Hydroids,  Jellyfish,  and  Sea  Anemones 

With  the  exception  of  a  few  species  all  of  the  Ccelenterata 
live  in  salt  water.  They  differ  from  most  of  the  animals 
thus  far  described  in  having  no  body  cavity  (ccelome)  sur- 
rounding the  digestive  canal  and  in  the  presence  of  only 
two  layers  of  cells  in  the  body  wall. 

Hydra  Viridis.  — This  common  freshwater  polyp  may  be 
found  in  the  summer  and  autumn  by  placing  in  several 
glass  jars  or  aquaria  a  considerable  quantity  of  duck-meat 
or  duck-weed,  together  with  the  water  in  which  it  is  found 
growing.  This  plant  is  a  favorite  support  for  the  animals. 
Place  the  jars  in  a  north  or  east  window  and  examine  them 
daily  for  a  week,  looking  through  the  water  toward  the 
light  for  a  minute  creature  a  fourth  of  an  inch  long  or  less 
with  tentacles.  It  is  usually  attached  to  the  side  of  the 
jar  toward  the  light.  When  found  it  may  be  transferred 
with  a  pipette  (medicine  dropper)  to  a  watch  crystal  for 
study  and  covered  with  a  few  drops  of  water. 

The  structure  of  the  Hydra  is  that  of  a  simple  tube  with 
walls  made  with  two  layers  of  cells,  the  outer  of  which  is 
the  ectoderm  and  the  inner  the  endoderm.  For  securing 
food  there  are  around  the  mouth  several  tentacles  bearing 
stinging  cells  (nematocysts)  containing  coiled,  whiplike 
processes  which  dart  forth  at  the  touch  of  an  animal  and 
numb  it.  The  tentacles  then  slowly  work  the  prey  through 
the  mouth  into  the  digestive  cavity  where  digestive  juices 
secreted  by  some  of  the  cells  render  parts  of  it  absorbable 
by  certain  cells  of  the  endoderm.  The  undigested  portions 
are  cast  out  through  the  mouth.  Water  fleas  and  algae 


CCELENTERATA   AND  PORIFERA 


169 


FIG.  195.  — Photograph  of  living  hydras.    Each  of  the 
two  at  the  right  bears  a  bud.  Twice  natural  size. 


form      much      of 

their    food.       No 

vascular,    respira- 

tory, or  excretory 

systems  are  pres- 

ent, and  the  ner- 

vous system  is  rep- 

resented  only   by 

a     few     scattered 

cells.      Delicate 

muscle  fibers  indicate  the  beginning  of  a  muscular   sys- 

tem   in    the    animal 
kingdom. 

Reproduction  oc- 
curs in  two  ways 
—  by  budding  and 
means  of  eggs. 
a  Hydra  be 
watched  a  few  min- 
utes each  day  for  a 
week,  a  minute  bud 
which  is  really  an 
outpushing  of  the 
wall  may  be  seen 
to  appear  and  grow 
larger  from  day  to 
day  for  a  period  of 
from  four  to  eight 
days  until  it  as- 
sumes the  form  of 
the  mother.  It  then 


by 
If 


?IG.  196.  —  Photograph  of  Hydra  enlarged  fifteen 
diameters.  The  minute  swellings  on  the  ten- 
tacles at  the  left  are  the  stinging  cells. 


170 


ANARTHROPODA 


breaks  loose  from  the  parent  and  leads  an  independent 
life. 

The  egg  which  is  merely  an  enlarged  and  specialized  cell 
near  the  base  of  the  parent  may  develop  into  a  complete 
polyp  (Hydra)  if  one  of  the  numerous  male  (sperm)  cells 
breaking  out  of  the  spermary  unites  with  it.  Soon  after 


FIG.  197.— Longitudinal  section  of  a  Hydra  ;  b,  bud  which  will  form  a  young  one ; 
6a,  base  by  which  it  is  attached  when  not  creeping ;  m,  mouth ;  ov,  ovary  with 
an  egg ;  sp,  spermary. 

the  union,  the  egg  separates  from  the  parent  and  dropping 
to  the  bottom  may  remain  there  over  winter  before  growing 
into  a  new  animal. 

Hydroids.  —  These  are  hydralike  animals  living  in  the 
ocean,  and  frequently  growing  in  colonies.  Obelia  is  a 
common  example  on  our  eastern  coast.  It  is  found  in 
colonies  attached  to  boards  and  seaweeds  near  the  surface 
of  the  water.  The  animals  composing  the  colony  are  called 


.  198. — Photograph  of  a  Hydra  reproducing  ;  a,young  bud  about  six  hours  old ; 
6,  bud  four  days  old ;  c,  base  fixed  to  a  stem.    Enlarged  thirty  diameters. 


FIG.  199.  — Several  hydroid  colonies  each  containing  from  10  to  20  animals,  growing 
on  a  piece  of  rotten  wood  in  the  ocean.  The  three  lowest  animals  on  the  tafl 
colony  in  the  middle  are  reproductive  polyps.  Photograph  enlarged  four 
diameters..  (171) 


172 


ANA&THBOPODA 


FIG.  200.  —  Several  hydroid  colonies  (Sertu- 
larid)  each  containing  from  20  to  30  animals. 
Photograph  enlarged  three  diameters. 


zoophytes  or  polyps  and 
each  has  the  same 
structure  as  the  Hydra. 
There  are  two  kinds  of 
polyps  One  is  known 
as  the  feeding  polyp, 
and  has  for  its  func- 
tion the  securing  and 
digesting  of  food  to  be 
distributed  throughout 
the  colony;  the  other  is 

the  reproductive  polyp  or  Uastostyle,  which  produces  the 

young.     The  food  polyps  are  recognized  by  the  tentacles 

absent  in  the  blastostyles  which 

contain  biscuit-shaped  bodies,  the 

medusae  buds.    These  one  by  one 

emerge    as   minute   umbrellalike 

forms  called  medusce.     ,        . 
They  swim  about  freely,  never 

attaining  a  sufficient  size  to  be 

seen  clearly  with  the  naked  eye, 

and  the    female   produces   eggs, 

while  the  male  gives  forth  sperm 

cells  each  of  which  uniting  with 

an  egg  fertilizes  it,  i.e.,  renders  it 

capable  of  developing  into  an  ani- 
mal.    The  young  one  soon  fixes 

itself  to  a  weed  or  stick,  and  in  a 

few  weeks  by  producing  budding 

young  like  the    Hydra   forms  a 

colony.    The  hydroids  are  there- 


FIG.  201.  — A  hydroid  colony  of 
six  polyps  ;  /,  feeding  polyp  ; 
r,  reproductive  polyp ;  m,  a 
medusa. 


CCELENTEEATA  AND   PORIFERA  173 

fore  said  to  exhibit  alternation  of  generations)  i.e.,  the  egg 
of  the  medusa  generation  does  not  hatch  into  a  medusa, 


FIG.  202.  —  Half  of  a  jellyfish  ;  a,  two  of  the  four  arms  around  the  mouth  m ;  r, 
reproductive  organs ;  st,  stomach  ;  t,  tentacles 


but  develops  into  a  fixed  colony  some  of  whose  polyps 
produce  medusa?  (small  jellyfish). 

The  large  jelly  fishes  of  the  ocean,  which  are  similar  hi 
structure  to  the  medusse  just  described,  attain  a  diameter 
of  several  inches  and  possess  tentacles  a  foot  or  more  long 


174 


ANARTHROPODA 


bearing  nematocysts.    The  stinging  sensation  one  experi- 
ences upon  picking  up  a  jellyfish  is  caused  by  the  discharge 


FIG.  203.  —  Development  of  young  jellyfish.    The  top  one  is  ready  to  break  away 
After  Haeckel. 

of  these  coiled  stinging  processes.  Each  egg  deposited  by 
the  jellyfish  produces  a  free- 
swimming  young,  which  soon 
fixes  itself  to  an  object  and 
assumes  a  form  similar  to  the 
hydra  and  grows  to  the  height 
of  half  an  inch.  It  then  be- 
comes transversely  divided  into 
several  parts,  giving  the  animal 
the  appearance  of  a  pile  of 
saucers.  The  top  one  soon 
swims  free,  and  one  by  one  the 

others  are  also  separated  and  turning  upside  down  lead 
the  free  life  of  the  adult  forms. 
The  sea  anemones  may  be  seen  at  low  tide  attached  firmly 


CCELENTERATA   AND  PORIFERA 


175 


to  the  rocks  and  wharves  a  short  distance  beneath  the  sur- 
face of  the  water.  They  vary  in  diameter  from  a  fourth 
of  an  inch  to  two 
feet.  Themoment 
they  are  disturbed 
the  numerous  ten- 
tacles around  the 
mouth  are  con- 
tracted, and  the 
fleshy  mass  be- 
comes a  brown 
conical  body. 

The  coral  polyp 
is  similar  to  the 
anemone,  but  much 
smaller.  It  secretes 
from  the  sea  water 
lime  which  is  de- 
posited throughout 
its  tissues  to  form 
a  skeleton.  Most 
corals,  like  the  hydroids,  bud  freely  and  thus  great  masses 
of  coral  are  formed.  They  dwell  only  in  the  warmer  parts 
of  the  ocean. 

Porifera:  Sponges 

The  sponges  are  mostly  ocean  dwellers,  only  about  thirty 
species  being  found  in  fresh  water.  A  simple  sponge,  such 
as  Grantia  or  Leucoselenia,  growing  near  the  surface  of  the 
water  on  logs  and  stones  along  the  Atlantic  coast,  has 
much  the  same  structure  as  Hydra,  but  the  walls  composed 


FIG.  205. —Coral.  Each  of  the  two  thousand  or 
more  small  projections  is  the  work  of  one  coral 
polyp.  Photograph,  one  third  natural  size. 


176 


ANARTHROPODA 


of  three  layers  are  perforated  by  numerous  minute  pores 
for  the  passage  of  water  and  food.  The  larger  sponges  are 
of  a  more  complex  nature. 

The  body  of  a  sponge  in  addition  to  the  fleshy  material 
consists  in  some  species  of  flexible  fibers  of  spongin,  such  as 
make  up  entirely  the  commercial  sponge  when  purchased. 

In  other  species 
like  Grantia, 
lime  spicules  are 
present,  and  in  a 
few  kinds,  in- 
cluding the  fresh 
water  forms,  sil- 
icious  spicules 
occur. 

The  fresh 
water  sponges 
have  a  wide  dis- 
tribution, and 
may  be  found 
by  looking  for  irregular  more  or  less  lobed  cushionlike 
masses  from  one  to  four  inches  in  diamster  attached  to 
weeds,  logs,  and  stones  in  clear  springs  and  ponds. 

Sponges  reproduce  by  eggs  and  also  by  internal  buds 
called  gemmules. 

In  the  ocean,  sponges  are  found  at  depths  of  from  one 
to  six  hundred  feet.  The  most  famous  sponge  fisheries 
are  those  of  the  Great  Bahama  Bank  in  the  West  India 
region,  and  those  of  the  Mediterranean  and  Red  Seas. 
All  sponges  came  from  the  Mediterranean  Sea  prior  to  the 
year  1840,  when  the  famous  fisheries  were  discovered  along 


-  A  fresh  water  sponge.    Photograph  natural 
size. 


CCELENTERATA   AND  PORIFERA  177 

the  Bahama  Islands.  Seven  or  eight  hundred  craft  are 
now  engaged  in  the  sponge  regions  of  the  West  Indies, 
where  the  shallow  water  permits  them  to  hook  up  the 
animals  with  a 
long-handled  three- 
pronged  fork  In 
the  Mediterranean 
Sea  the  finest 
sponges  grow  at 
a  depth  of  two 
hundred  feet  or 
more,  and  can  be 
secured  only  by 
divers,  many  of 
whom  work  with- 
out diving  suits 
and  remain  under 
water  as  long  as 
three  minutes.  The 
deepest  sponges  are 
brought  up  with 
drag  nets. 

The    skeleton    Of        ^IG"    207-~  A  salt  water  sponge.    Photograph  half 
.  natural  size. 

the    commercial 

sponge  composed  of  fine  spongin  fibers  is  cleaned  free  of  the 
fleshy  portion  by  means  of  bacteria  which  cause  all  flesh  to 
decay  or  rot.  Some  species  of  sponges  are  found  growing 
only  on  the  backs  and  legs  of  certain  crabs  which  are  thereby 
concealed  from  their  enemies.  The  crab  favors  the  sponge  by 
carrying  it  to  new  feeding  grounds.  Such  mutually  help- 
ful association  between  animals  is  termed  commensalism. 


178  ANARTHROPODA 


14.   PROTOZOA:  ONE-CELLED  MICROSCOPIC  ANIMALS 

The  members  of  this  phylum  are  single-celled  animals, 
and  so  small  that  but  few  of  them  can  be  seen  with  the 
naked  eye,  and  some  are  so  minute  as  to  be  visible  only 
under  the  highest  powers  of  the  microscope.  They  abound 
in  the  dust  of  the  air,  in  the  surface  layers  of  the  earth, 
and  in  the  water,  while  many  parasitic  forms  make  their 
homes  in  the  living  bodies  of  the  higher  animals  and  plants, 
sometimes  causing  disease. 

Slipper  Animalcule  (Paramoecium). — This  is  a  repre- 
sentative of  the  class  Infusoria,  which  includes  most  of  the 

protozoa  commonly  pres- 
ent in  infusions  made  by 
soaking  grass,  leaves,  or 
flowers  in  water.  Para- 
moecia  may  usually  be  se- 
cured by  placing  a  bunch 

FIG.  208.  — Slipper  animalcule  showing  t     i         <,,.„««     i^     fl     plioV,     nf 

the  nucleus,  a  dark  circle,  and  the 

buccai  groove  on  the  lower  side.  En-      stagnant  water  f or  a  week 

larged  two  hundred  diameters. 

or  two. 

For  study,  a  small  drop  of  water  containing  a  number 
of  specimens  should  be  transferred  to  a  glass  slip,  and  one 
or  two  minute  threadlike  green  plants  added  to  the  drop 
before  the  cover  glass  is  placed  thereon.  Having  seen  with 
the  low  power  that  the  animals  wanted  are  present  in  the 
mount,  absorb  with  blotting  paper  the  superfluous  water 
about  the  edge  of  the  cover  glass,  drop  near  its  margin  a 
half  dozen  pieces  of  paraffin,  and  with  a  red-hot  nail 
held  in  a  cork  melt  the  paraffin  so  it  runs  slightly  over  the 


PROTOZOA 


179 


edge  of  the  cover  glass  and  thus  makes  an  air-tight 
aquarium.  I  have  kept  amoeba  and  some  of  the  smaller 
infusoria  alive  in  this  way  over  two  months.  The  Para- 
mcecia  usually  live  only  a  few  days.  The  preparation  must 
be  kept  in  the  light,  not  sun,  so  that  the  plants  will  give 
off  the  oxygen  ne- 
cessary to  the  life 
of  the  animals  and 
also  consume  their 
excreted  carbon 
dioxide. 

The  movement 
of  the  animal  is 
effected  by  short, 
hairlike  processes 
(cilia)  covering 
the  entire  surface. 
The  buccal  groove 
beginning  on  one 
side  opens  into  a 
mouth  permitting 
the  food  to  pass  through  a  short  gullet  into  the  soft  in- 
ternal protoplasm  (cell  contents).  They  feed  largely 
on  bacteria.  Near  either  end  of  the  body  may  be  seen  a 
clear  round  spot,  the  contractile  vacuole,  which  is  an  exit 
for  the  surplus  water. 

Paramoecium,  like  all  other  infusorians,  reproduces  by 
binary  fission,  i.e.,  divides  its  body  into  two  equal  parts, 
each  of  which  in  a  day  or  two  grows  to  the  normal  size. 
This  process  of  division  is  easily  seen,  as  about  a  half  hour 
is  required  for  its  completion.  Each  of  the  new  genera- 


FlG.  209.  —  Living  Paramcecia  photographed  through 
the  microscope  magnifying  eighty  diameters. 


180 


ANARTHROPODA 


tion  is  ready  to  divide  again  within  twenty-four  hours  if 
the  conditions  are  favorable.  After  the  formation  of  a 
hundred  or  more  generations  they  seem  to  become  ex- 
hausted and  must  then  be  rejuvenated  by  a  process  called 
conjugation.  This  is  the  union  of  two  individuals  along 
their  ventral  surfaces  by  means  of  which  a  mutual  ex- 
change of  protoplasm  occurs.  They  then  separate,  and 
each  is  ready  to  divide  again. 

Bell  Animalcule  (Vorticella).  —  This  is  another  infusorian 
common  in  stagnant  water.     It  is  easily  recognized  under 

the  low  power  of  the 
microscope  by  its 
bell-shaped  body 
attached  to  a  stem 
which  occasionally 
contracts  into  a 
spiral.  The  cilia 
around  the  mouth 
are  used  to  form 
a  vortex  drawing 
the  food  into  its 
gullet  leading 
blindly  into  the 
soft  protoplasm. 

Amoeba.  —  This 
genus  includes  sev- 


FIG. 210. — Photograph  of  a  living  bell  animalcule, 
enlarged  two  hundred  diameters. 


eral  species  of  the  class  Rhizopoda  (root-footed),  which  are 
regarded  as  being  the  lowest  in  the  scale  of  animal  life. 
Seldom  does  one  become  large  enough  to  be  seen  with  the 
naked  eye,  but  it  is  easily  distinguished  with  a  magnifica- 
tion of  one  or  two  hundred  diameters.  In  some  regions 


PROTOZOA 


181 


the  Amoeba  is  not  easy  to  secure,  but  if  a  few  sticks  and 
leaves  with  their  accompanying  ooze  from  a  stagnant  pond 
be  placed  in  a  dish  of  water  in  an  east  or  north  window, 


FIG.  211.—  A,  Amoeba  proteus;    B,  Amoeba  radlosa.   n,  nucleus;    c,  contractile 
vacuole  ;  a,  food  engulfed  ;  ec,  one  of  the  nine  pseudopods.    After  .Leidy. 

and  a  little  green  scum  or  water  alga3  added,  large  numbers 
usually  develop.  To  secure  them  for  study,  scrape  a  little 
of  the  slime  from  a  stick  or  leaf  upon  a  glass  slip,  place  on 
the  cover  glass,  and  examine  with  the  low  power.  An 


182  AHAHTHROPODA 

Amoeba  may  be  recognized  by  its  slow  crawling  and  fre- 
quent changes  in  shape  as  it  puts  forth  the  blunt  processes 
called  pseudopods.  It  appears  like  a  mass  of  granular  color- 
less protoplasm  streaming  along  inside  of  &  transparent  sac 
known  as  the  ectosarc.  It  has  no  mouth  but  secures  food 
by  wrapping  itself  about  any  organic  material  which  then 
passes  through  the  ectosarc  into  the  soft  protoplasm,  called 
endosarc,  capable  of  digesting  it.  The  products  excreted 
by  the  lungs  and  kidneys  of  the  higher  animals  are  also 
excreted  by  the  one  cell  forming  the  amoeba. 

For  continued  study,  the  Amoeba  should  be  mounted  as 
directed  for  Paramcecium.  Some  of  them  may  then  be 
seen  taking  on  globular  shapes  and  surrounding  themselves 
with  a  kind  of  cyst  or  coat.  In  this  condition  they  are  said 
to  be  encysted,  and  are  capable  of  thus  existing  in  a  dried 
state  for  months.  While  encysted  they  often  divide  into 
several  parts  called  spores,  each  of  which  upon  the  bursting 
of  the  cyst  forms  a  complete  animal.  They  also  reproduce 
by  binary  fission,  but  this  method  is  not  common. 

Parasitic  Forms.  —  Several  species  of  protozoans  are 
dwellers  in  the  higher  groups  of  animals  from  worms  to 
man.  Amceba  coli  lives  in  the  intestines  of  man  and  causes 
a  severe  kind  of  dysentery.  Plasmodiwn  malarice  is  always 
present  in  the  blood  corpuscles  of  patients  suffering  from 
any  of  the  malarial  fevers.  Mosquitoes  of  the  genus 
Anopheles  (Fig.  371)  transfer  the  parasites  from  the  sick 
to  the  healthy,  and  thus  a  large  part  of  an  entire  community 
may  become  infected  with  this  germ.  It  belongs  to  the 
class  Sporozoa,  which  is  so  named  because  the  animals  in 
reproducing  divide  into  a  number  of  small  bodies  called 
spores. 


PROTOZOA 


183 


FIG.  212.  —  Photograph  of  human  red  blood  corpus- 
cles two  of  which  contain  the  malarial  parasite. 
Enlarged  one  thousand  times. 


Chalk     formers. 

—  The  Globigerince 

are  among  the  most 

abundant  protozoa 

in  the  sea.     Nearly 

all  surround  them- 
selves with  a  shell 

of  soft  calcium  car- 
bonate (chalk).    A 

pint  of  ocean  water 

in    the    warmer 

climes  may  contain 

millions   of  them. 

The   shells  of  the 

dead  dropping  to 

the  bottom  of  the  ocean  have  formed  a  thick  layer  of  ooze 

over  much  of  the  ocean  bed.  The  great  chalk  cliffs  in 
England,  and  the  chalk  beds 
in  Ireland,  Denmark,  Central 
Europe,  North  Africa,  Syria, 
Central  Asia,  Texas,  Kansas, 
and  South  Dakota  are  com- 
posed almost  entirely  of  the 
shells  of  GlobigerinaB  that  lived 
ten  millions  of  years  ago  or 
more.  The  small  piece  of  chalk 
used  by  the  carpenter  is  made 
of  millions  of  the  skeletons  of 
these  tiny  protozoans. 
The  protozoa  were  no  doubt 

FIG.   213.  —  Shell    of    Globigerina.  r 

Photograph  enlarged  forty  diameters,      the     first       animals     On      earth, 


184 


ANARTHROPODA 


FIG.  214.— Photograph  of  the  Protozoans  in  one  twentieth  of  a  drop  of  stagnant 
water. 

and  inasmuch  as  two  new  animals  are  formed  by  the  halving 
of  the  parent  the  tiny  creatures  may  never  die  of  old  age, 
but  so  long  as  food  and  environment  are  favorable  live 
millions  of  years.  They  are  therefore  sometimes  spoken 
of  as  the  immortal  animals.  The  Protozoa  are  most  numer- 
ous in  stagnant  water  where  as  many  as  ten  thousand  may 
be  present  in  a  single  drop.  Ordinary  drinking  water, 
however,  seldom  contains  more  than  a  dozen  in  a  quart, 
and  good  spring  water  often  has  none, 


PART  III 
VERTEBRATA 

15.  PISCES 

THE  four  chief  orders  of  this  class  are  the  round-mouthed 
fish  (Cyclostomata),  the  cartilaginous  fish  (Elasmobranchii) , 
the  bony  fish  (Teleostomi),  and  lung  fish  (Dipnoi). 


FIG.  215. — Ocean  lamprey.    Photograph  one  fourth  natural  size.    The  holes  oi\ 
the  side  behind  the  eyes  are  the  gill  openings. 

135 


186 


VERTEBRATA 


Round-mouthed  Fish.  — There  are  about  a  dozen  species 
in  this  country,  of  which  the  commonest  is  the  ocean  lam- 
prey (Petromyzon  marinus)  attaining  a  length  of  more  than 

two  feet.  It  as- 
cends the  streams 
along  the  Atlantic 
coast  to  the  distance 
of  more  than  a  hun- 
dred miles  for  the 
purpose  of  spawn- 
ing, which  in  the 
latitude  of  New  York 
occurs  about  the 
middle  of  May.  The 

FIG.  216.— Photograph  of  the  mouth  of  a  living  lam-       nest       is       made       of 
prey  sucked  fast  to  a  piece  of  glass.    Natural  size. 

gravel  and  sand  en- 
circled by  stones  nearly  as  large  as  a  man's  head,  which 
they  suck  fast  to  with  their  peculiar  mouth  and  drag 


FIG.  217.  — Median  longitudinal  section  of  the  anterior  fourth  of  a  lamprey  eel. 
6,  brain ;  c,  spinal  cord ;  m,  muscles  of  the  back  ;  n,  notochord  ;  I,  liver ;  h, 
heart.  Photograph. 

together.  The  larval  young  (Ammoccetes)  bury  themselves 
in  the  mud  along  the  banks  of  the  streams,  where  they 
remain  three  or  four  years  until  transformation  to  the  adult 


PISCES  187 

state  occurs.  They  then  descend  to  the  ocean  and  remain 
there  several  years,  after  which  they  return  to  the  scene 
of  their  youth  for  breeding  purposes,  and  a  few  days  later 
die  without  having  regained  the  ocean.  The  adult  is  a 
parasite  living  on  the  blood  and  mucus  rasped  from  the 
sides  of  fish.  The  lake  lamprey  of  New  York  is  probably 
a  descendant  of  the  ocean  lamprey,  having  been  cut  off 
from  the  salt  water  by  the  drying  up  of  the  streams  many 
years  ago.  It  is  destructive  to  food  fishes,  preying  on 
nearly  thirty  different  species. 

The  lampreys  are  not  true  fish,  as  they  lack  paired  fins 
containing  spines  or  bony  rays,  and  have  only  one  nostril, 
which  opens  on  top  of  the  head  in  the  median  line.  Jaws 
are  wanting.  The  skull  is  made  of  membrane  and  carti- 
lage, and  the  spinal  cord  lies  in  a  fibrous  tube  with  bars 
of  cartilage  along  the  sides.  Beneath  the  spinal  cord  is  a 
stiff  gelatinous  rod  known  as  the  notochord,  which  is  pres- 
ent in  the  very  young  stages  of  all  vertebrates,  but  usually 
its  place  is  later  occupied  by  the  bodies  of  the  bony  verte- 
bra? (Fig.  227). 

Cartilaginous  Fish.  —  The  fish  whose  skeletons  are  made 
of  cartilage  instead  of  bone  live  in  salt  water.  They  are 
the  sharks  and  rays.  Many  of  them  are  predaceous  crea- 
tures, and  their  presence  accounts  for  the  scarcity  of  some 
of  the  species  of  fish  desired  for  food  by  man. 

The  sharks  are  represented  along  our  coast  by  several 
species,  of  which  the  best  known  is  the  dogfish  (Squalls 
acanthias),  which  attains  a  length  of  three  feet.  During 
the  summer  it  congregates  in  great  numbers  along  the 
Maine  and  Massachusetts  coasts,  and  often  prevents  the 
fishermen  from  catching  any  codfish  by  seizing  the  bait 


188  VEBTEBRATA 

the  moment  it  is  thrown  into  the  water.  In  1883  their 
vast  numbers  completely  destroyed  the  fishing.  They  bit 
the  sails  or  oars  hanging  over,  and  even  attacked  persons 
falling  overboard.  They  were  caught  by  the  thousands, 
their  livers  being  used  for  oil  and  their  bodies  carted  to 


FlG.  218.  —  The  young  of  the  dogfish  removed  from  the  body  of  its  parent.  Ventral 
aspect  showing  the  attachment  of  the  large  yolk  sac  to  the  body,  and  also  the 
crescentic  mouth.  Five  gill  slits  are  seen  on  one  side.  Photograph  half  natural 
size. 

the  farms  for  fertilizer.    They  feed  upon  refuse  and  smaller 
fish. 

The  blue  sharks  and  basking  sharks  of  the  northern  Atlan- 
tic reach  a  length  of  over  thirty  feet,  while  the  Indo- Pacific 
basking  shark  is  known  to  exceed  forty  feet  in  length.  The 
man-eater  or  white  shark,  ranging  from  the  Atlantic  coast 
to  Australia,  seldom  attains  a  size  of  more  than  thirty  feet. 


PISCES  189 

In  some  species  of  sharks  the  young  are  born  alive,  but 
in  others  the  eggs  are  deposited  in  a  tough,  usually  flattened 
case  with  tendrils  by  which  it  may  be  fixed  to  seaweeds. 
Most  of  the  one  hundred  and  fifty  species  of  sharks  are 
characterized  by  five  gill  openings  on  either  side  of  the  head, 
underneath  which  the  mouth  is  situated. 

The  rays  differ  from  the  sharks  in  having  the  gill  open- 
ings beneath  the  flat  disk  formed  by  the  body  and  the  ex- 
panded pectoral  fins.  The  common  skate  of  our  Atlantic 
coast  (Raja  erinacea)  grows  to  a  length  of  nearly  two  feet 
and  is  nearly  as  broad.  The  sawfishes,  some  of  which  are 
fifteen  feet  long,  are  remarkable  for  the  prolongation  of  the 
snout  in  a  saw-edged  sword  nearly  one  fourth  the  length 
of  the  fish.  They  range  from  Cape  Cod  southward.  Not 
less  noted  is  the  electrical  fish  (Torpedo  marmoratus)  found 
along  the  New  England  coast.  A  specimen  two  or  three 
feet  long  is  capable  of  imparting  a  severe  shock  to  any  one 
seizing  it  along  the  sides  of  the  body. 

Bony  Fish    (Teleostomi). — This  order  is  made  up  of 


FIG.  219.  —  The  bull  head  (a  catfish).      Photograph  one  fourth  natural  size. 

thousands  of  species  which  are  characterized  by  a  bony 
skeleton,  usually  a  scale-covered  body,  and  gills  protected 
by  a  plate  projecting  backward  called  the  operculum. 


190  VERTEBRATA 

The  catfishes  have  a  scaleless  skin,  a  pair  or  two  of  long 
barbels  (feelers)  projecting  from  the  upper  jaw,  and  the 
first  ray  of  the  dorsal  and  pectoral  fins  is  a  stout  spine  with 
which  the  animal  can  inflict  serious  wounds.  There  are 
nearly  a  thousand  species  widely  distributed  over  the  world 
and  are  highly  valued  as  food.  The  great  catfish  of  the 
Mississippi  River  attains  a  length  of  five  feet  and  weighs 
one  hundred  and  fifty  pounds.  The  Bullhead  or  horned 
pout  (Ameiurus  coins)  is  common  in  streams  east  of  the 
Mississippi.  The  eggs  of  some  species  are  deposited  under 
objects  in  the  streams  and  guarded  by  the  male,  while  in 
other  species  the  eggs  are  carried  in  the  mouth  until 
hatched. 

The  suckers  are  covered  with  scales,  have  toothless  jaws, 


FIG.  220.— Common  river  Sucker  (Catostomus  teres).  Photograph  one  third  natural 
size. 

and  thick,  fleshy  lips  forming  a  nearly  circular  mouth. 
They  feed  on  plants  and  small  animals.  The  flesh  is  used 
for  food,  but  is  rather  coarse. 

The  herringSj  of  which  there  are  more  than  a  hundred 
species,  are  found  in  many  parts  of  the  ocean,  and  some 
come  to  the  fresh  water  to  spawn  (lay  eggs).  The  common 
herring  (Clupea  harengus),  about  a  foot  long,  frequents  the 
north  Atlantic  coast  where  they  associate  in  shoals  number- 


PISCES  191 

ing  millions  and  swim  near  the  surface  to  secure  the  worms, 
insects,  and  crustaceans.  They  are  therefore  easily  taken 
in  nets. 

The  shad  (Clupea  sapidissima)  is  an  important  food  fish, 
passing  the  greater  part  of  its  life  in  the  ocean  along  the 
Atlantic  and  Pacific  coasts.  When  mature  it  ascends  a 
stream,  often  traveling  more  than  a  hundred  miles  to  de- 
posit its  eggs,  numbering  many  thousands.  On  these  trips 
the  fish  are  caught  with  seines.  Like  the  lampreys,  a  few 


FIG.  221.— Photograph  of  the  shad  one  sixth  natural  size. 

days  after  spawning  they  die.  The  shad  fisheries  of  the 
Atlantic  coast  are  worth  two  millions  of  dollars  annually. 
The  salmon  are  the  most  valuable  of  all  the  food  fishes. 
The  five  species  of  the  Pacific  coast  salmon,  canned  in  such 
immense  quantities,  yield  an  annual  revenue  of  thirteen 
million  dollars.  During  most  of  their  life  they  live  in  the 
ocean,  but  ascend  a  stream,  often  two  or  three  thousand 
miles,  to  spawn,  after  which  they  die.  It  is  during  their 
migration  for  breeding  purposes  that  they  are  caught  in 
such  vast  numbers.  The  quinnat  or  chinook  salmon,  attain- 
ing a  weight  of  fifty  pounds,  affords  the  most  delicious 
meat,  but  they  have  become  somewhat  scarce  lately  owing 


192 


VERTEBRATA 


to  the  vast   numbers  caught.     A  few  species  of  salmon 
inhabit  the  streams  along  the  north  Atlantic  coast. 

The  trout  are  the  most  delicious  of  all  the  food  fishes. 
Of  these    the    brook  trout    (Salvelinus  fontinalis),   orna- 


Fio.  222.  —  The  brook  trout.     Photograph  one  third  natural  size. 

men  ted  with  red  spots,  is  the  most  famous.  It  inhabits 
the  cold  streams  from  Maine  to  Dakota,  and  is  often  culti- 
vated in  ponds.  Owing  to  insufficient  protection  by  law, 
the  supply  is  becoming  limited. 

The  cave  fishes  are  represented  by  several  species  in  this 
country,  dwelling  in  subterranean  streams.    Those  living 


PIG.  223.  —  Photograph  of  the  common  mackerel  one  third  natural  size. 


in  the  Mammoth  Cave  of  Kentucky  are  white  and  entirely 
blind.  Their  ancestors  possessed  eyes,  but  lack  of  use 
throughout  many  generations  resulted  in  blindness.  Quite 
as  remarkable  as  the  cave  fish  are  the  flying  fish  of  the  ocean. 
They  dart  obliquely  out  of  the  ocean  and  spread  the  broad 


PISCES  193 

fins  which  act  as  parachutes,  enabling  them  to  soar  through 
the  air  nearly  an  eighth  of  a  mile. 

The  sea  horse  (Hippocampus)  is  a  member  of  the  pipe- 
fish family.  It  is  only  a  few  inches  long,  and  dwells  in  the 
ocean.  The  male  cares  for  the  young  in  an  abdominal 
pouch. 

The  codfishes  number  ninety  species,  of  which  Gadus 
callarius  is  the  most  important.  It  reaches  a  length  of 
four  feet.  In  November  each  mature  female  deposits 
about  ten  millions  of  eggs  which  hatch  floating  on  the  sur- 
face of  the  sea.  Vast  numbers  of  codfish  are  caught  with 
hooks  and  lines  along  the  north  Atlantic  and  Pacific  coasts, 
and  are  much  valued  for  food  both  in  the  fresh  and  salted 
state. 

The  mackerels  include  about  seventy  species,  all  living 
in  salt  water.  They  frequent  the  northern  shores  at  the 
spawning  season  in  early  summer  when  they  appear  in 
large  schools.  At  this  time  great  numbers  of  the  common 
mackerel  (Scomber  scombrus)  are  taken  in  nets  along  the 
New  England  coast.  Those  not  sold  fresh  are  packed  in 
brine. 

The  sunfishes  number  a  dozen  species  in  the  United 
States.  The  green-  sunfish  (Lepomis  cyanellus),  six  or  seven 
inches  long,  is  common  in  the  small  streams  east  of  the 
Mississippi.  In  early  summer  it  forms  a  nest  more  than  a 
foot  in  diameter  in  shallow  water.  Coarse  gravel  lines  the 
margin  of  the  concave  area  and  near  the  center  very  fine 
gravel  is  present  on  which  the  eggs  are  deposited.  The 
male  remains  over  the  nest,  keeping  it  clear  of  dirt  with 
the  tail,  until  the  eggs,  of  wliich  there  are  several  thousand, 
hatch. 


VERTEBRATA 


FlG.  224.  —  Green  sunfish  on  her  nest.    Photograph  one  fifth  natural  size. 

The  flatfishes  or  flounders  are  valuable  food  fish  of  the  sea. 
The  halibut  is  the  largest,  weighing  four  hundred  pounds, 
but  the  flounder  (Pleuronectes  americanus)  is  most  fre- 
quently seen  in  market.  It  is  remarkable  for  having  two 
eyes  on  one  side  of  the  head  and  none  on  the  other.  It 
swims  on  the  side,  the  lower  surface,  which  is  white,  always 
remaining  in  that  position.  The  young  are  symmetrical, 
having  an  eye  on  either  side  of  the  head  and  swimming 
upright. 

Lungfishes  (Dipnoi).  —  In  this  order  only  three  species 
are  included.  They  live  in  Australia,  Africa,  and  South 


PISCES 


196 


FIG.  225.  — Photograph  of  the  flounder  from  the  lower  side.    Half  natural  size. 

America.  The  feature  from  which  the  group  takes  its 
name  is  the  possession  of  a  lung  or  lungs  corresponding  in 
position  to  the  air  bladder  in  other  fish.  Gills  are  also 
present,  so  that  these  fish  can  live  either  in  water  or  on  land. 


PIG.  226. — Lepido  siren,  the  South  American  lungfish.     Photograph   one  fourth 
natural  size. 


196  VERTEBRATA 

The  African  mudfish  buries  itself  in.  the  mud  for  several 
months  during  the  dry  season. 

The  members  of  the  class  Pisces  are  distinguished  from 
all  other  vertebrates  by  the  absence  of  limbs,  the  presence 
of  gills  throughout  their  entire  life,  and  a  simple  heart  con- 
sisting of  only  one  auricle  and  one  ventricle.  The  fish, 
amphibians,  and  reptiles  are  often  referred  to  as  the  cold- 
blooded animals  and  the  other  two  classes,  birds  and 
mammals,  as  warm-blooded  animals.  This  distinction  is 
due  to  the  fact  that  the  two  higher  classes  maintain  a  con- 
stant temperature  of  from  ninety-eight  to  one  hundred 
and  five  degrees  Fahrenheit  whether  the  surrounding  at- 
mosphere be  hot  or  cold.  A  fish,  frog,  or  snake  varies  its 
temperature  in  accordance  with  that  of  the  atmosphere. 
In  winter  they  may  have  a  temperature  near  the  freezing 
point,  while  in  summer  it  may  be  almost  a  hundred  degrees. 

The  air  bladder,  present  in  all  forms  except  the  round- 
mouthed  fish,  flatfish,  sharks,  and  rays,  lies  on  the  dorsal 
side  of  the  body  cavity  above  the  alimentary  canal  and 
in  some,  such  as  the  herring  and  trout,  opens  by  a  duct 
into  the  pharynx.  Usually,  however,  the  contained  gas 
is  given  off  through  the  walls.  Its  function  is  to  aid  the 
fish  in  maintaining  its  position  in  the  water. 

To  understand  the  parts  of  a  fish  one  of  the  smaller 
species,  such  as  the  catfish,  sunfish,  or  porgy,  should  be 
dissected  after  the  external  features  have  been  noted.  An 
eye  lies  in  a  deep  socket  on  either  side  of  the  head,  and 
is  capable  of  rotation  in  several  directions  by  means  of 
muscles.  No  eyebrows  or  eyelids  are  present,  as  in  higher 
forms.  The  nostrils  are  two  pairs  of  small  openings  near  the  • 
tip  of  the  nose.  They  lead  into  the  nasal  cavity  over  which 


PISCES  197 

the  olfactory  nerve,  the  nerve  of  smell,  is  distributed.  This 
cavity  does  not  communicate  with  the  mouth,  as  in  the 
Dipnoi  and  all  the  higher  vertebrates.  There  is  no  external 
ear.  The  scales,  overlapping  each  other  like  the  shingles  of 
a  house,  are  calcified  outgrowths  of  the  skin  to  protect 
the  body.  The  unpaired  dorsal  fins  vary  from  one  to  three. 
A  pair  of  pectoral  fins  is  present  just  back  of  the  gill  open- 


FIG.  227.  —  Dissected  fish,  a,  air  bladder  ;  b,  urinary  bladder  ;  6r,  brain  ;  c,  spinal 
cord  ;  d  and  da,  dorsal  fins  ;  dv,  anal  fin  ;  e,  body  of  the  vertebrae  ;  g,  gills  re- 
ceiving the  blood  from  the  ventral  aorta  leading  out  of  the  heart  h  ;  i,  intestine  ; 
k,  kidney ;  I,  liver ;  m,  spines  of  the  vertebrae ;  n,  auricle  of  the  heart ;  ov, 
ovary ;  ovd,  oviduct ;  st,  stomach  ;  sp,  spleen ;  M,  ureter.  Drawing  by  W.  H. 


ing,  and  behind  and  below  these  is  usually  a  pair  of  ventral 
fins.  The  anal  fin  present  in  some  forms  is  single,  and 
behind  the  opening  of  the  alimentary  canal.  By  removing 
the  entire  ventral  abdominal  wall,  most  of  the  organs  may 
be  seen. 

Teeth  are  usually  present  not  only  on  the  jaws,  but  in 
some  species  on  the  vomer  at  the  roof  of  the  mouth  and 
on  the  gill  arches.  Vertical  openings  between  the  four 


198  VERTEBRATA 

gill  arches  are  the  gill  slits  permitting  the  water  to  pass 
from  the  pharynx  to  the  exterior.  The  flap  covering 
the  gills  externally  is  the  operculwn.  A  narrow  tube,  the 
gullet  or  esophagus,  leads  from  the  large  pharynx  to  the 
stomach,  from  which  extends  the  somewhat  tortuous  intes- 
tine to  its  opening  at  the  root  of  the  tail.  The  liver  may 
be  recognized  by  its  large  size  and  red  color. 

The  intestine,  as  well  as  the  other  organs,  is  held  in  place 
by  a  transparent  membrane  known  as  the  mesentery.  This 
is  a  part  of  the  peritoneum,  which  appears  as  a  thin,  glisten- 
ing membrane  lining  the  entire  abdominal  cavity  and 
closely  enveloping  most  of  the  organs  therein.  The  elon- 
gated narrow  white  organ  is  the  pancreas,  adjacent  to  which 
there  is  in  most  species  a  small  dark  red  body,  the  spleen. 
The  reproductive  organs  lying  dorsal  of  the  stomach  are 
white  in  the  male  and  yellowish  in  the  female.  The  air 
bladder  with  a  wall  as  thin  as  paper  is  of  a  grayish-white 
color,  and  lies  against  the  spinal  column.  To  see  the 
kidneys,  one  must  look  carefully  for  a  pair  of  flattened 
brown  bodies  lying  closely  against  the  vertebral  column 
in  the  dorsal  side  of  the  body  cavity. 

With  a  heavy  knife  the  top  of  the  skull  may  be  removed, 
and  the  parts  of  the  brain  with  several  of  the  ten  pairs  of 
nerves  issuing  from  its  ventral  aspect  noted.  By  cutting 
away  the  roof  of  the  spinal  column,  the  spinal  cord,  and 
each  nerve  connected  with  it  by  two  roots  may  be  observed. 
The  eye  cut  into  with  a  sharp  knife  reveals  three  coats: 
an  outer  tough  one,  the  sclerotic;  a  thin  black  one,  the 
choroid;  and  an  inner  pinkish  one,  the  retina.  The  almost 
round  crystalline  lens  lies  between  the  watery  or  aqueous 
humor  contained  in  the  front  chamber  of  the  eye  and  the 


AMPHIBIA  199 

glassy  or  vitreous  humor  filling  the  posterior  chamber  of 
the  eye.  The  ear  composed  of  the  three  semicircular 
canals  opening  into  the  oval  sac,  called  the  vestibule,  may  be 
seen  in  part  by  shaving  off  the  side  of  the  skull  in  the  pos- 
terior part. 

16.   AMPHIBIA 

The  Amphibians,  often  called  Batrachians,  derive  their 
name  from  the  fact  that  many  of  the  species  live  a  part 
of  their  life  on  land  and  breathe  by  lungs,  while  the  other 
part  is  spent  in  the  water  where  gills  must  be  used.  The 
members  of  this  class  are  distinguished  from  both  the  fish 
and  the  reptiles  by  the  absence  of  scales.  They  are  divided 
into  three  orders,  the  Urodela,  Anura,  and  Gynmophiona. 


FIG.  228.  —  Photograph  of  newts  nearly  natural  size. 


VERTEBRATA 


Urodela:  Salamanders 

This  order  is  characterized  by  the  presence  of  a  tail. 
The  neivt  (Diemyctylus  viredescens)  may  be  seen  from 
March  to  December  in  quiet  ponds  of  water  and  captured 


FIG.  229.  —  Photograph  of  large  blunt-nosed  salamander  fouad  under  a  stone  at  the 
water's  edge,    One  third  natural  size. 


FIG.  230.  — Photograph  of  Amblysloma  opacum  half  natural  size. 

with  the  net  for  the  aquarium.  It  relishes  bits  of  beef 
and  earthworms,  and  will  devour  a  hundred  mosquito 
larvae  daily. 


AMPHIBIA  201 

The  large  blunt-nosed  salamander  (AmUystoma  tigrinum) 
and  the  gray  species  (Amblystoma  opacum)  may  often  be 
dipped  up  with  a  long-handled  net  from  the  sluggish  waters 
near  woodlands  where  they  come  in  early  spring  to 
breed.  The  eggs,  numbering  several  hundred,  appear  like 
shot  in  a  colorless,  jelly  like  mass  of  albumen  as  large 
as  the  human  fist. 

The  red-backed  salamander  (Plethodon  cinereus)  is  com- 


FlQ.  231.  —  Plethodon  cinereus.    Photograph  natural  size. 

mon  under  stones  and  logs  in  and  near  the  woods.  The 
mountain  salamanders  of  the  genus  Desmognathusare  often 
found  under  the  loose  stones  in  the  cold  forest  streams  of 
the  liighlands.  Though  most  of  the  amphibians  have 
lungs  in  the  adult  state  the  species  of  the  genera  Spelerpes 
and  Plethodon  have  neither  gills  nor  lungs  when  mature. 
The  blood  is  relieved  of  its  carbon  dioxide  and  receives 
oxygen  by  means  of  the  capillaries  lying  near  the  surface 


202 


VERTEBRATA 


FlG.  232.  —  Home  of  the  salamanders. 


AMPHIBIA 


203 


of  the  skin  and  in  the  mucous  membrane  of  the  mouth 
and  throat. 

The   mud  puppy    (Necturus   maculatus),   abundant  in 
the  Great  Lakes  and  the  waters  near  by,  is  remarkable 


FIG.  233.  — Desmognathus,  the  mountain  salamander.    Photograph  natural  size. 

in  that  it  possesses  both  gills  and  lungs  in  the  adult  state. 
Like  characters  are  exhibited  by  the  blind  salamander  (Pro- 
teus anguineus)  in  the  caves  of  Austria  and  an  allied  form 


FIG.  234.  —Photograph  of  Amblystoma  eggs  in  water.    Natural  size. 


found  in  the  caves  of  Texas.  The  hellbender  (Crypto- 
branchus  alleghaniensis)  is  the  largest  of  our  salamanders. 
It  lives  in  the  streams  of  the  Ohio  and  the  Susquehanna 
valleys.  The  congo  snake,  which  reaches  a  length  of 
nearly  three  feet,  inhabits  the  ditches  and  stagnant  ponds 


204  VERTEBRATA 

from  Arkansas  to  North  Carolina.     Its  limbs,  two  or  three- 
toed  and  less  than  an  inch  long,  illustrate  the  effect  of  dis- 


FIG.  235.— The  mud  puppy  or  water  dog,  showing  the  gills  projecting  from  either 
side  of  the  neck.    Photograph  one  third  natural  size. 

use  of  an  organ.  The  mud  eel  (Siren  lacertina)  of  South 
Carolina  is  similar  to  the  congo  snake  in  habits  and  form, 
but  has  no  poste- 
rior limbs  and  ex- 
hibits external 
gilts  like  the  mud 
puppy 


Anura  :   tailless 
*  Amphibia 

This  order  in- 
cludes the  frogs 
and  toads  which 
are  found  in  nearly 
all  parts  of  the 

FIG.  236.  —  Photograph  of  fbo  congo  snake  one  third 
WOrld.          In       the  natural  sizfc 


FIG.  237.  — The  green  frog,  showing  the  tympanic 
membrane  (ear  drum)  just  back  of  the  eye.  Pho- 
tograph half  natural  size  by  Overton. 


AMPHIBIA  205 

adult  stage  they  are  provided  with  lungs,  but  respiration 
is  carried  on  to  a  large  extent  through  the  skin,  especially 
in  the  frogs  spend- 
ing much  time  under 
the  water. 

The  bull  frog 
(Rana  catesbiana)  is 
the  only  amphibian 
much  valued  for 
food.  The  length  of 
a  full-grown  speci- 
men from  the  tip  of 
the  nose  to  the  end 
of  the  outstretched 
hind  legs  is  nearly  two  feet.  It  may  be  distinguished  from 

the  other  frogs  by  the 
fact  that  the  web  of  the 
foot  reaches  to  the  tip  of 
the  fourth  toe  and  the 
back  is  of  a  greenish  color 
with  small  faint  dark 
spots.  Thousands  of  dol- 
lars' worth  of  frogs'  legs 
are  sold  annually  in  the 
city  markets.  The  green 
frog  (Rana  clamitans)  is 
characterized  by  a  tym- 
panic membrane  larger 
than  the  eye  and  the 

FIG.  238.  —  The   common  tree  frog  two  thirds 

natural  size.      Photograph  was  taken  just       presence      of      a      fold      OH 
after  it  was    transferred  from  a  sheet  of 

white  paper.     Twenty  minutes  later  it  was       pitViPr   csirlp    nf 
the  same  color  as  the  oak  bark. 


206  VERTEBRATA 

The  commonest  of  our  frogs  is  the  leopard  frog    (Rana 
pipiens)  distinguished  by  the  two  rows  of  irregular  black 

blotches  on  the  back  and 
the  bars  on  the  upper  surface 
of  the  legs. 

The  tree  frogs  or  tree  toads 
are  so  named  from  their 
habit  of  climbing  trees,  to 
which  they  adhere  by  means 
of  small  expansions  at  the 
extremities  of  the  toes. 
They  have  the  power  to 
change  their  color  to  har- 
monize with  their  surround- 
ings. The  common  tree  frog 
(Hyla  versicolor)  is  the  one 
FIG.  239.— The  spring  peeper,  photo-  giving  the  high  trilling  note 

graph  natural  size.  ,       .  „    ,, 

prophetic  of  the  approach- 
ing storm;  The  Spring  peeper  (Hyla  pickeringii)  an- 
nounces the  coming  spring  by  its  clear  shrill  whistle 
"  Uh-e-e-t,  wh-e-e-t,  wh-e-e-t," 
uttered  so  continuously  at  night- 
fall that  every  meadow  and  swamp 
seems  to  be  the  home  of  thou- 
sands. They  may  be  caught  by 
wading  among  them  with  a  lan- 
tern and  then  remaining  quiet 
about  ten  minutes  until  one  moves  FIG.  240. -The  toad  one  third 
sufficiently  near  to  be  grasped.  natural  8ize* 

Toads  differ  from  frogs  in  having  no  teeth  in  either  jaw, 
and  usually  the  skin  presents  a  warty  appearance.    The 


AMPHIBIA  207 

frogs  prefer  moist  places,  but  the  toads  seek  a  dry  habitat 
in  yards  and  gardens 
where  they  are  of  great 
service  in  destroying 
flies,  slugs,  and  noxious 
insects.  One  hundred 
and  forty-nine  toad 
stomachs  examined  by 
Kirkland  showed  three 
fourths  of  the  food  to 
consist  of  insects  of 
which  one  fourth  were 
cutworms  and  tent  cat- 
erpillars. The  stomach 

Of    Olie  toad   Contained        FlG   241._Larva  of  Amblystoma  and  of  the 
fifty-five    army  WOrms  ^r°g»  three  months  old.    Photograph  natural 

and    that    of    another 

thirty-seven  tent    caterpillars.     Bufo    lentigenosus   is  the 

only  species  of  toad  east  of  the  Rocky  Mountains. 

Gymnophiona 

The  members  of  this  order  are  tailless  and  limbless 
forms,  living  in  Southern  India,  Southern  Africa,  and  Cen- 
tral and  South  America.  They  are  covered  with  scales, 
and  in  other  ways  resemble  snakes. 

The  breeding  habits  of  the  majority  of  the  amphibians 
are  similar.  The  eggs  are  usually  deposited  in  the  water, 
but  the  congo  snake  protects  hers  beneath  a  log  or  stone, 
while  a  South  American  frog,  Pipa,  carries  the  eggs  im- 
bedded in  the  skin  of  the  back.  The  eggs  of  most  of  the 


208  VERTEBRATA 

frogs  and  the  Amblystoma  appear  as  dark  bodies  of  pin- 
head  size  imbedded  in  a  mass  of  clear,  jellylike  albumen. 
The  eggs  of  the  toad  are  deposited  in  strings.  The  newt 
fastens  its  eggs  singly  within  little  tufts  of  aquatic  leaves, 
while  Plethodon  hides  its  eggs  under  stones  arid  logs  on 
land. 

The  time  of  year  when  the  various  species  breed  extends 
from  March  to  October.  The  eggs  of  the  Amblystoma  and 
the  leopard  frog  are  found  as  soon  as  the  snow  melts  in 
the  spring,  while  the  green  frog  and  brown  frog  spawn  in 
April.  In  May  or  June  the  common  tree  frog  attaches  its 
eggs  in  small  masses  to  stems  of  weeds  and  grass  in  shallow 
pools,  and  the  bullfrog  seldom  spawns  before  July.  The 
toad  scatters  its  strings  of  eggs  over  the  stones  and  brush 
in  any  small  pool  or  pond  during  late  April  and  early  May. 
The  breeding  season  of  the  newts  extends  from  April  to 
July,  and  some  of  the  large  urodels  lay  their  eggs  in  the 
autumn. 

The  young  of  the  amphibians  are  known  as  larvce  or  tad- 
poles. They  dwell  in  the  water  and  breathe  by  means  of 
gills.  In  the  case  of  frogs  and  toads,  the  food  consists 
largely  of  vegetable  matter,  which  fact  accounts  for  the 
great  length  of  the  intestine  in  these  forms.  The  intestine 
of  the  adult  feeding  on  animals  is  not  one  fourth  as  long  as 
that  of  the  larva.  The  Amblystoma  larvaB  feed  on  aquatic 
insects,  such  as  mosquito  larvae  and  pupae,  and  therefore 
have  a  short  intestine,  as  nutrition  is  easily  secured  from 
animal  matter.  The  length  of  the  larval  period  varies  in 
the  different  species.  For  the  toad  it  is  usually  about  two 
months,  while  in  some  frogs  it  lasts  six  months  and  in 
others  more  than  a  year.  Many  of  the  salamanders  pass 


AMPHIBIA 


209 


the  winter  in  the  larval  stage,  and  one  species  of  the  Ainbly- 
stoma,  the  Axolotl,  continues  throughout  life  in  the  larval 
state,  unless  forced  to  terrestrial  habits  by  the  drying  up 
of  the  water.  In  the  Anura,  metamorphosis  to  the  adult 
state  involves  the  absorption  of  the  gills  and  the  tail,  and 
the  development  of  lungs,  and  an  exchange  of  animal  for 
a  vegetable  diet.  After  the  first  few  days  of  larval  life, 


FIG.  242.  —  Frog  with  the  left  side  cut  away  and  some  of  the  organs  pulled  down- 
ward, a,  aorta  leading  from  the  ventricle ;  6,  bladder ;  c,  spinal  cord  sur- 
rounded by  the  vertebral  column  of  bone  ;  d,  small  intestine  ;  e,  opening  of  the 
lungs  into  the  pharynx ;  h,  ventricle  of  the  heart ;  k,  kidney  ;  I,  lung ;  Jiv,  liver  ; 
n,  brain ;  ov,  ovary  ;  ovd ,  oviduct  ;  p,  pancreas  ;  r,  rectum  ;  sp,  spleen  ;  st, 
stomach ;  t,  tongue ;  si,  small  intestine  ;  tt,  left  auricle  ;  ur,  ureter ;  v,  vena 
cava ;  vc,  body  of  vertebra. 

the  frogs  and  toads  do  not  have  external  gills  like  the  sala- 
manders, but  the  gills  are  on  arches  and  covered  similar  to 
those  in  fish,  but  only  one  opening  exists,  and  that  is  a  small 
one  on  the  left  side  just  behind  the  head. 

Dissection.  —  Those  wishing  to  study  the  structure  of 
this  class  by  making  a  careful  dissection  may  use  any  of 
the  salamanders,  a  large  tadpole,  or  a  frog,  which  can 


210  VERTEBRATA 

be  easily  killed  by  immersing  a  quarter  of  an  hour  in  a 
half  pint  jar  of  water  containing  an  ounce  of  one  per 
cent  chloretone  or  a  quarter  of  an  ounce  of  chloroform. 
A  frog  is  preferable  for  this  work.  Before  killing,  its 
method  of  respiration  and  locomotion  should  be  noted. 
Among  the  external  features  to  be  observed  are  the  moist, 
smooth  skin,  the  teeth  in  the  upper  jaw,  the  peculiar  tongue, 
the  two  minute  apertures,  called  external  nares,  at  the  tip 
of  the  nose,  the  two  eyes,  each  with  two  eyelids  of  which 
the  lower  is  the  more  movable,  the  circular  tympanic  mem- 
brane just  back  of  the  eye,  and  the  webbed  condition  of 
the  feet.  The  three  parts  of  the  fore  limb  are  the  arm, 
forearm,  and  hand,  with  the  four  digits  corresponding  to 
the  four  fingers  of  man.  The  thumb  is  scarcely  large 
enough  to  be  noted.  The  parts  of  the  hind  limb  are  the 
thigh,  leg,  and  foot,  with  the  five  toes  webbed  together. 
To  study  the  internal  features,  cut  off  with  the  scissors 
the  entire  ventral  wall  of  the  abdomen,  lay  the  frog  on  its 
back  in  a  waxed-bottom  dissecting  pan  containing  enough 
water  to  cover  the  animal.  Pin  down  the  sides  of  the 
abdominal  wall  and  identify  the  various  organs  by  the  use 
of  the  illustration  and  comparison  with  the  same  struc- 
tures in  a  fish.  If  the  animal  is  a  male,  the  sexual  glands 
will  be  two  oval  solid  yellowish  bodies  near  the  kidneys. 
The  delicate  membrane  supporting  the  intestine  is  the 
mesentery,  which  is  a  part  of  the  peritoneum,  the  thin 
glistening  membrane  lining  the  body  cavity  and  closely 
surrounding  most  of  the  organs.  The  heart  of  the  amphibia 
is  composed  of  a  ventricle  and  two  auricles  in  addition  to 
a  venous  sac  and  an  arterial  trunk.  The  circulation  of  the 
blood  may  be  observed  under  the  microscope  in  the  tail 


REPTILIA  211 

of  a  tadpole.  To  make  one  lie  quiet  on  a  glass  slip  with  a 
cover  glass  over  its  tail,  immerse  it  in  the  chloretone  mix- 
ture (water  one  part  and  one  per  cent  chloretone  five  parts) 
until  completely  unconscious.  A  drop  of  blood  put  on  a 
clean  glass  slip  and  at  once  spread  very  thin  by  drawing 
the  end  of  another  glass  slip  lightly  over  it  will  show  the 
oval  nucleated  red  corpuscles  characteristic  of  most  of 
the  vertebrates  except  mammals. 

The  brain  with  its  ten  pairs  of  nerves  joining  its  ventral 
aspect  may  be  seen  by  cutting  away  the  roof  and  sides  of 
the  skull  with  a  heavy  knife.  Any  one  wishing  to  study 
the  skeleton  can  render  the  flesh  easily  removable  by  boil- 
ing the  animal  an  hour  or  more,  depending  upon  its  age, 
in  two  quarts  of  water  containing  an  ounce  of  soap  cut  into 
slices. 

17.   REPTILIA 

The  reptiles  are  distinguished  from  the  amphibians  by 
the  presence  of  scales  and  the  fact  that  the  young  never 
breathe  by  gills.  Only  three  orders  inhabit  this  country. 
They  are  the  Squamata  (snakes  and  lizards),  the  Chelonia 
(turtles  and  tortoises),  and  the  Crocodilia  (crocodiles  and 
alligators. 

Squamata:   Lizards  and   Snakes 

The  name  of  this  order  is  derived  from  the  Latin  squama, 
a  scale.  The  distinguishing  feature  of  the  group  is  the 
presence  of  horny  epidermal  scales  covering  the  surface. 

The  Lizards.  —  More  than  eighty  species  of  lizards  are 
known  in  North  America.  They  differ  from  the  snakes 


212 


VERTEBRATA 


in  not  having  a  forked  tongue  and  in  having  eyelids  and  an 
external  ear  opening  on  either  side  of  the  head.  The 
common  lizard  (Sceleporus  undulatus)  is  widely  distributed 
over  the  United  States.  The  skinks  or  striped  lizards  are 
fast  runners  and  abound  in  the  central  and  southern  por- 
tion of  our  country. 

The  chameleon  (Anolis  principalis)  is  the  grass  green 
lizard  of  the  South,  which  is  capable  of  changing  its  color 


FlG.  243.  — The  horned  chameleon  from  Africa.    Photograph   two  thirds  natural 

size. 

to  harmonize  with  its  surroundings  and  thus  escape  the 
eyes  of  the  enemy.  The  chameleon  famed  in  literature  is 
from  Africa. 

The  glass  snake  (Ophisaurus  ventralis),  ranging  from 
Wisconsin  to  Kansas  and  south,  is  remarkable  for  the  com- 
plete absence  of  limbs.  More  than  twenty  species  of  limb- 
less lizards  are  known.  There  are  a  dozen  species  with 


REPT1LIA  213 

hind  limbs  only,  and  two  or  three  species  in  which  fore 
limbs  only  are  present.  The  study  of  fossil  reptiles  shows 
that  the  ancestors  of  these  forms  had  well-developed  limbs 
which  degenerated  on  account  of  the  habits  of  the  animals  ; 
they  spend  much  time  in  narrow  quarters  where  legs  are 
useless  and  a  hindrance. 

The  only  poisonous  lizard  in  this  country  is  the  Gila 
monster   (Heloderma  suspedum)  living  in  Arizona,  Cali- 


FIG.  244.— The  Gila  monster.     Photograph  one  fifth  natural  size. 

fornia,  and  Mexico.  The  largest  specimens  measure  nearly 
a  yard.  Allied  to  these  are  the  huge  monitor  lizards  of 
Africa,  India,  and  Australia,  which  attain  a  length  of  seven 
feet.  Most  lizards  are  oviparous,  depositing  their  eggs 
in  the  sand. 

The  Ophidia.  — The  snakes,  numbering  one  hundred  and 
fifty  species  in  North  America,  are  much  more  elongated 


214 


VERTEBRATA 


than  the  lizards,  and  with  the  exception  of  very  few  species 
possess  no  remnants  of  hind  limbs. 

The  family  Colubridce  includes  most  of  our  harmless 
snakes.  The  commonest  of  our  garter  snakes  (Thnmnophis 
sirtalis)  frequents  yards,  gardens,  and  fields  hi  search  of 
mice,  frogs,  and  insects.  Like  all  snakes,  they  swallow 

their    prey    whole 

and  sometimes 
alive.  The  lower 
jaw  is  so  loosely 
attached  to  the 
skull  as  to  permit 
the  throat  to  be 
greatly  enlarged 
and  the  alimentary 
canal  may  likewise 
become  much  ex- 
panded owing  to 
the  fact  that  the 
ribs  are  not  artic- 
ulated to  a  breastbone,  as  in  birds  and  mammals,  but 
terminate  freely.  The  prey  after  being  swallowed  may 
remain  alive  some  time  in  the  stomach.  I  once  shot  a 
water  moccasin  (Natrix  sipedon)  and  upon  opening  the 
stomach  an  hour  later  found  seven  fish,  three  of  which 
swam  away  when  placed  in  water. 

The  milk  snake  or  spotted  adder  (Lampropeltis  triangu- 
laris)  frequents  the  neighborhood  of  houses,  and  is  often 
mistaken  for  the  copperhead  pilot.  When  disturbed  it 
mimics  the  poisonous  snakes,  but  is  entirety  harmless.  The 
black  snake  or  blue  racer  (Bascanion  constrictor)  frequents 


FIG.  245. — A  garter  snake  two  feet  long  and  the 
frog  which  it  swallowed.    Photograph. 


KEPTILIA 


215 


FlG.  246.—  Thamnophis  sirtalis  three  feet  long.     Photograph. 


FIG.  247.  —  Water  snake  or  moccasin  often  found  along  the  streams.  Three  feet 
long.  Below  is  the  skin  which  it  shed  entire  just  before  the  photograph  was 
made. 


216 


VERTEBRATA 


FIG.  248.  — Spotted  adder  nearly  three  feet  long. 
Photograph. 


pasture  grounds  and 
woods  east  of  the 
Mississippi,  attains  a 
length  of  seven  feet, 
but  is  entirely  harm- 
less. It  is  fond  of 
birds'  eggs  and  birds 
which  it  often  climbs 
trees  to  secure. 

Crotalidce  is  the 
family  including  all 
our  poisonous  snakes, 
except  one  species, 
the  bead  snake,  rang- 
ing from  Virginia  to 
Arkansas  and  the 

South.     There  are  no  external  features  which  enable  one 

to  determine  with 

certainty  at  sight 

whether  any  snake 

is     venomous     or 

harmless,     but     a 

flattened     head, 

constricted     neck, 

short  tail,  and  pit 

in  front  of  the  eye 

give  unmistakable 

evidence  that  the 

reptile  is  a  veno- 
mous  one.      Two 

fangs  perforated  or   Ko.  ^..Bl!Mksu^ tam (eet long.  Photograpl, 


EEPTILIA 


217 


grooved  are  present  in  the  front  part  of  the  upper  jaw  of 
all  venomous  snakes.  The  red  forked  tongue  darted 
quickly  back  and  forth  is  by  many  wrongly  supposed  to  be 
the  sting  of  the  snake. 

The  only  venomous  serpents  of  our  country  are  the 
rattlesnakes,  copperhead  pilot,  cotton  mouth  or  southern 
moccasin,  harlequin,  and  coral  or  bead  snake. 

The  rattlesnakes,  which  are  not  found  outside  of  America, 
number  about  a 
dozen  species  in  the 
United  States.  They 
are  characterized  by 
the  possession  of 
from  three  to  fifteen 
horny  buttons  at 
the  end  of  the  tail. 
The  number  of  these 
buttons  or  rattles 
does  not  tell  the  age 
of  the  reptile,  as  two 
or  three  are  grown 
in  a  year,  while  one 
or  more  may  be  lost. 
The  poison  lying  in 
a  sac  just  below  each  eye  passes  out  through  a  duct  lead- 
ing through  the  center  of  the  fang.  The  bite  is  usually 
fatal  to  man  in  from  ten  to  fifteen  hours,  unless  some 
remedy  is  used.  A  deep  gash  should  be  made  with  a  knife 
so  as  to  let  the  poisoned  blood  escape  from  the  wound, 
and  if  in  an  extremity  a  tight  bandage  should  be  placed 
above  it  to  prevent  the  poison  from  reaching  the  other 


FIG.  250.  —Rattlesnake  three  feet  long  coiled  ready 
to  strike.  In  this  position  it  can  dart  its  head  for- 
ward two  feet  only.  Photograph. 


218 


VERTEBRATA 


parts  of  the  system  and  paralyzing  the  nerves  controlling 
the  heart  and  lungs.  Wliiskey  is  useful  to  stimulate  the 
latter  organs  and  a  large  quantity  of  milk  should  be  drunk 


FIG.  251.  —  A,  venomous  snake  (Copperhead)  ;   B,  harmless  snake.     Photograph 
natural  size. 

until  vomiting  occurs  several  times.     In  the  mean  time  a 
physician  should  be  sent  for  to  administer  hypodermically 


FIG.  252.  —  Copperhead  with  mouth  open  and  fangs  erected  as  when  biting.    Photo- 
graph natural  size. 

the  proper  antidotes,  which  are  potassium  permanganate 
or  chromic  acid  in  the  proportion  of  one  part  of  the  chem- 
ical to  one  hundred  parts  of  water. 
The  copperhead  or  pilot    (Ancistrodon  contortrix)  is  a 


REPTILIA 


219 


dangerous  reptile  found  in  the  Eastern  and  Central  States 
in  moist  lands  and  near  woodlands.     The  same  treatment 


FIG.  253.  —  A  copperhead  three  feet  long.  Photograph. 

as  that  directed  for  the  rattlesnake  prevents  the  bite  from 
resulting  fatally. 
The  southern  water  mocassin  (Ancistrodon  piscivorous) 


FIG.  254.  — Ph 


nty-foot  python  ill  the  Philadelphia  Zoological 
Gardens. 


220 


VERTEBRATA 


FIG.  265.  —  Boa  constrictor  crushing  a  rat  prepara- 
tory to  swallowing  it.    Photograph. 


is  a  very  venomous  snake  in  the  South,  resting  on  bushes 
overhanging  streams  watching  for  its  favorite  food,  con- 
sisting of  frogs  and 
fish.  The  Cobra 
( Naja  tripudians ) , 
attaining  a  length  of 
four  feet,  is  a  deadly 
snake  living  in  India 
where  it  is  much 
feared  because  dur- 
ing the  wet  season 
it  seeks  protection 
in  the  huts  of  the 
natives.  About 
twenty  thousand  people  and  several  thousand  cattle  are 
killed  annually  by 
its  bite. 

The  family  Boidce 
includes  the  largest 
of  living  snakes. 
They  are  non-veno- 
mous but  dangerous, 
owing  to  their  abil- 
ity to  crush  a  deer 
or  man  by  coiling 
about  him.  A  pecu- 
liar feature  exhibited 
by  them  is  the  presence  of  rudimentary  hind  limbs.  The 
Indian  python  attains  a  length  of  twenty-five  feet  and  a 
diameter  of  ten  inches.  The  Anaconda,  inhabiting  South 
America,  is  the  largest  of  all  snakes.  Specimens  have 


FIG.  256.  — Skull    of    Boa   constrictor    two   thirds 
natural  size.    Photograph. 


REPT1LIA  221 

been  seen  more  than  thirty  feet  long.  Among  the  true 
Boas,  found  in  Madagascar  and  tropical  America,  the  best 
known  is  the  Boa  constrictor  of  South  America,  about 
thirteen  feet  in  length. 

The  epidermis  or  outer  skin  of  snakes  is  shed  two  or 
three  times  a  year  and  usually  in  a  single  piece.  The 
young  of  some  species,  such  as  the  rattlesnake  and  moccasin, 
are  born  alive,  while  others,  such  as  the  black  snake,  grass 
snake,  and  milk  snake,  are  hatched  from  eggs  deposited 
in  the  ground.  Snakes  pass  the  cold  weather  in  a  sleep- 
ing state  beneath  rocks  and  logs  or  in  holes  in  the  ground. 


Crocodilia 


The  crocodiles  are  represented  by  only  two  species  in 
this  country:  The  Alligator  Mississipiensis  and  Crocodilus 
acutus  floridanus.  Both  dwell  in  the  lowlands  of  the  South. 


FIG.  257.  — Photograph  of  a  young  alligator  four  feet  long  in  the  Philadelphia 
Zoological  Gardens. 

Their  food  consists  largely  of  fish,  but  the  larger  alligators 
from  ten  to  fifteen  feet  long  sometimes  attack  mammals, 
dragging  them  into  the  water  where  they  are  drowned. 
There  are  about  twenty  species  of  crocodiles  and  alligators 
living  in  other  countries.  Some  of  them  attain  a  length 
of  twenty  feet  and  are  dangerous  to  man. 


222  VERTEBRATA 

The  crocodilians  reproduce  by  laying  from  thirty  to 
sixty  oblong  white  eggs  as  large  as  those  of  a  hen,  in  a 
mound  of  muck,  vegetable  mold,  or  sand.  Sufficient 
heat  to  hatch  them  is  furnished  by  the  sun  and  the  fer- 
mentation in  the  decaying  mound.  The  young  of  our 
species  are  more  than  six  inches  long  when  born. 

Chelonia  or  Testudinata:  Tortoises  and  Turtles 

The  members  of  this  order  are  characterized  by  a  more 
or  less  fully  developed  bony  shell  investing  the  body  and 
by  the  absence  of  teeth. 

They  are  widely  distributed  throughout  the  warmer 
regions  of  the  globe,  about  fifty  species  being  known  in  the 

United  States. 

The  name  tortoise 
is  applied  to  those 
forms  having  strong 
legs  with  unwebbed 
feet  adapted  to  pro- 
gression on  land. 
The  commonest  rep- 
resentatives east  of 
the  Rocky  Moun- 
tains are  the  box 
tortoise  ( Terrapene 

FIG.  258.  —  Box  tortoise  seen  from  beneath  to  show  Carolina)  and  the 
the  hinge  joint.  One  fifth  natural  size.  Photo-  Wf)od  tOTtOlSB  (Clem- 
graph  by  D.  S.  Hartline. 

mys  insculpta).     In 

the  box  tortoise  the  dorsal  shell,  called  carapace,  is  strongly 
arched   and  of  variable  colors,  blackish  and  yellowish. 


223 


The  ventral  shell,  the  plastron,  has  a  transverse  hinge  near 
the  middle.  The  wood  tortoise  has  a  keeled  carapace, 
the  plates  of  which  are  marked  with  concentric  striae 
and  radiating  black  bands.  In  the  Gallapagos  Islands 
very  large  tortoises  are  found,  one  of  which,  the  elephant 
tortoise,  attains  a  length  of  five  feet  and  is  able  to  carry  a 
man. 

The  term  terrapin  is  used  to  designate  those  tortoises 
having  more  or  less  of  a  web  between  the  toes  so  that  they 
are  adapted  to  both  terrestrial  and  aquatic  life.  The 


painted  terrapin  (Chry semis  picta)  is  so  called  on  account 
of  the  bright  red  markings  on  the  margins  of  the  shell. 
It  is  abundant  everywhere  along  the  ponds  and  streams 
of  the  eastern  United  States.  Large  numbers  sit  on  the 
logs  and  the  stones  at  the  water's  edge  sunning  them- 
selves, and  at  the  approach  of  any  one  glide  into  the 
water.  Several  species  of  terrapins  are  much  prized  for 
food.  The  snapping  turtle  (Chelydra  serpentina),  attaining 
a  length  of  two  feet,  is  common  throughout  most  of 
North  America.  Soup  made  from  it  is  greatly  in  demand. 
It  is  a  fierce  carnivorous  reptile  feeding  on  ducks,  chick- 
ens, frogs,  and  other  aquatic  animals. 


224  VERTEBRATA 

The  true  turtles  differ  from  the  tortoises  in  having  limbs 
flattened  for  swimming  and  only  two  of  the  toes  bearing 
claws.  They  dwell  in  the  ocean  and  only  come  to  shore 
for  the  purpose  of  depositing  their  eggs  in  the  sand  to 


FiQ.  260. — Loggerhead  turtle  one  week  old.    Photograph  about  natural  size. 

hatch.  The  green  turtle  is  the  source  of  the  far-famed 
turtle  soup.  The  loggerhead  turtle  of  Florida  and  the  West 
Indies  resembles  the  green  turtle,  but  is  less  prized  for  food. 
The  tortoise  shell  of  commerce  is  derived  from  the  hawk- 
bill  turtle  (Chelone  imbricata)  which  is  more  than  two  feet 
in  length. 


REPTILIA  225 

All  chelonians  are  similar  in  their  habits  and  structure. 
The  eggs  varying  in  number  from  five  to  more  than  one 
hundred  are  deposited  in  the  ground.  They  may  be  dis- 
tinguished from  those  of  snakes  by  the  fact  that  they  are 
nearly  spherical.  The  period  during  which  the  eggs  are 
incubated  by  the  heat  of  the  sun  varies  in  different  species 
from  one  to  four  months.  The  land  chelonians  pass  the 
cold  weather  in  a  dormant  state  under  logs  and  stones  or 
in  self-constructed  burrows  in  the  earth,  while  the  terra- 
pins and  turtles  bury  themselves  in  the  mud. 

Dinosauria :  Giant  Lizards 

The  Dinosauria  form  an  order  of  extinct  land  reptiles 
which  inhabited  the  earth  more  than  ten  millions  of  vear? 


FIG.  261.  —  Dinosaur  three  feet  long,  restored  from  a  study  of  the  skeleton  found  to 
Connecticut. 

ago.  All  that  is  known  of  them  has  been  learned  from  the 
study  of  their  fossil  remains  found  in  the  rocks  of  Europe, 
India,  South  Africa,  and  North  America.  All  had  limbs, 


226  VERTEBRATA 

and  in  many  species  the  hind  ones  were  much  larger  than 
the  front  ones,  indicating  that  the  animals  walked  on  two 
legs  similar  to  the  birds.  The  bones  are  hollow,  as  in  birds, 
and  since  in  several  other  important  features  the  skeleton 
is  similar  to  that  of  birds  it  is  believed  that  the  two  groups 
are  closely  related  and  have  descended  from  a  common 
parent.  Many  species  were  of  immense  size.  Bronto- 
saurus,  the  giant  reptile  whose  mounted  stone  skeleton  is 
in  the  Museum  of  Natural  History  in  New  York,  was  over 
sixty  feet  long.  Diplodocus,  whose  fossil  remains  may  be 
seen  in  the  Carnegie  Museum  of  Pittsburg,  was  about 
seventy  feet  in  length.  The  extinction  of  this  entire  group 
of  huge  creatures  may  have  been  brought  about  by  lack 
of  food  or  the  presence  of  numerous  parasitic  or  carnivor- 
ous enemies. 

The  reptiles  are  intermediate  in  structure  between  the 
amphibians  and  birds.  The  brain  resembles  that  of  the 
frog,  but  the  cerebrum  is  larger.  The  vascular  and  respira- 
tory systems  approach  the  condition  in  birds.  In  most 
forms  the  heart  has  two  auricles  and  one  ventricle*  but 
in  the  crocodile  a  partition  divides  the  ventricle  into  two 
parts. 

18.   AVES 

The  birds  are  distinguished  from  all  other  vertebrates 
by  the  presence  of  feathers.  The  two  anterior  limbs  are 
modified  into  the  form  of  wings  adapted  for  flying  or  swim- 
ming. They  differ  from  the  three  preceding  classes  in 
being  warm-blooded,  having  a  temperature  of  from  one 
hundred  and  two  to  one  hundred  and  nine  degrees.  As  an 


AVES 


227 


assistance  to  flight  most  birds  are  able  to  decrease  the 
specific  gravity  of  the  body  by  means  of  a  series  of  air  sacs 
communicating  with  the  lungs.  The  larger  sacs,  usually 
about  a  dozen  hi  number,  lie  in  the  trunk  region,  but  smaller 
ones  sometimes  occur  in  the  bones,  which  are  hollow  in^ 
stead  of  being  filled  with  marrow 
as  in  the  mammals.  All  birds  are 
oviparous  (lay  eggs),  some  species 
depositing  as  many  as  two  hun- 
dred eggs  in  a  season,  while  others 
lay  only  one  each  year. 

No  modern  bird  possesses  any 
teeth,  but  the  fossil  remains  from 
Kansas  show  that  the  birds  living 
millions  of  years  ago  had  sharp, 
reptile-like  teeth.  The  most  an- 
cient bird  known  is  Archceopteryx, 
about  the  size  of  a  crow.  It  pos- 
sessed a  long,  jointed  tail,  numerous 
sharp,  conical  teeth,  claws  on  the 
wing,  and  many  other  reptilian 
characteristics.  These  facts  indi- 
cate that  the  birds  have  descended 
from  a  reptile-like  ancestor. 

Within  the  history  of  man  a  number  of  species  of  Aves 
have  become  extinct,  and  reports  from  nearly  every  state 
show  that  unless  quick  and  effective  protection  is  afforded 
our  feathered  friends,  irreparable  damage  may  result  to 
the  country.  Special  investigations  made  by  Hornaday 
show  that  the  average  decrease  in  bird  life  throughout  the 
United  States  from  1883-1898  was  forty-six  per  cent. 


FIG.  262.  —  Diagram  of  the 
lungs  and  air  sacs  of  a  pig- 
eon, p,  air  sacs  ;  lu,  lung  ; 
t,  trachea. 


228  VERTEBRATA 

Reports  from  Maine,  Rhode  Island,  Pennsylvania,  Indiana, 
North  Dakota,  Georgia,  Louisiana,  and  Texas  stated  that 
more  than  half  their  birds  had  disappeared,  while  observers 
from  Connecticut,  Florida,  and  Montana  agreed  that  the 
numbers  of  birds  in  those  states  had  decreased  by  seventy- 
five  per  cent.  The  seriousness  of  these  facts  becomes 
apparent  only  when  we  realize  that  recent  investigations 
have  shown  that  there  is  as  much  truth  as  poetry  in  the 
lines  of  Longfellow  • 

"The  summer  came  and  all  the  birds  were  dead; 
The  days  were  like  hot  coals;  the  very  ground 
Was  burned  to  ashes ;  in  the  orchards  fed 
Myriads  of  caterpillars,  and  around 
The  cultivated  fields  and  garden  beds 
Hosts  of  devouring  insects  crawled,  and  found 
No  foe  to  check  their  march  till  they  had  made 
The  land  a  desert  without  leaf  or  shade." 

A  careful  study  of  the  birds  emphasizes  the  necessity  of 
making  children  familiar  with  their  value,  not  only  from 
an  economic  standpoint,  but  also  from  an  aesthetic  view. 
With  the  exception  of  the  English  sparrow,  the  cow  bird, 
two  species  of  hawks,  and  the  great  horned  owl,  all  birds 
of  our  country  are  man's  friends. 

There  are  about  thirteen  thousand  species  of  birds  in 
the  world,  but  not  more  than  eight  hundred  species  occur 
in  the  United  States,  and  seldom  is  any  one  locality  favored 
with  more  than  two  hundred  kinds.  But  few  lovers  of 
nature  can  expect  to  become  familiar  with  more  than  fifty 
species  in  one  region.  The  identification  of  birds,  espe- 
cially the  warblers,  vireos,  and  sparrows,  in  the  bush  or  on 
the  wing,  is  not  an  easy  task,  but  if  the  beginner  proceeds 


229 


patiently  and  systematically  he  will  be  able  to  acquaint 
himself  with  a  score  or  more  of  birds  during  any  summer 
month.  When  a  new  bird  is  seen,  the  observer  should 
write  an  accurate  description  of  it  in  his  notebook,  giving 
the  length  from  the  tip  of  the  bill  to  the  end  of  the  tail; 
the  color  of  the  crown  and  sides  of  the  head,  back,  wings, 
tail,  breast,  and  belly;  length,  shape,  and  color  of  the  bill; 

Occiput  Forehead 
x  -Lores 

Upper  Ma  n  dible 

werMandible 


Lateral Hectn 
iMiddle 

Rectrices  ^    \ 

(Hallux) 


IjinerToe 
Middle  Toe 

Outer  Toe 
FIG.  263.  —  Names  used  in  describing  a  bird.    Drawing  by  Reese. 


length,  position,  and  arrangement  of  the  tail  feathers;  and 
the  method  of  feeding  and  manner  of  flight  as  well  as  its 
characteristic  song.  Such  a  record  will  enable  one  to 
identify  the  stranger  by  comparison  with  the  descriptions 
given  in  such  books  as  "  Bird  Neighbors  "  or  Chapman's 
"  Bird  Life."  The  brief  descriptions  and  illustrations  in 
the  following  pages  will  help  the  pupil  to  determine  the 
names  of  some  species. 


230 


VERTEBRATA 


FIG.  264.  —  Kingbird  at  its  nest.    Photographed  in  the  Museum  of  Natural  History, 
New  York.     One  third  natural  size. 


AVES 


231 


The  birds  are  grouped  into  about  twenty  orders,  of 
which  only  the  eight  most  important  ones  will  be  dis- 
cussed. 

Passeres :  Perching  Birds 

This  order  includes  approximately  one  half  of  our  species. 
They  may  be  recognized  by  the  presence  of  four  un webbed 
toes  all  on  the  same  level  and  with  joints  in  number  2,  3, 
4,  5,  respectively  from  the  first  (inner)  toe  to  the  fourth 
(hind).  All  our  song  birds  belong  to  this  group,  of  which 
the  families  here  given  have  representatives  in  most  local- 
ities. 

Flycatchers  (Tyrannidae) .  —  The  members  of  this  family 


FIG.  265. — Phoebe  with  its  mud  nest  in  the  corner  of  an  old  boathouse.  Photo- 
graphed in  the  Academy  of  Natural  Sciences,  Philadelphia.  One  third  natural 
size. 

are  so  named  because  they  feed  largely  on  aerial  insects 
which  they  seize  in  flight.    Hornaday  says  every  flycatcher 


232 


VERTEBRATA 


-Hunting   crows'  eggs  in  March. 
Photograph  by  Neal. 


is  worth  double  its 
weight  in  silver  to 
the  farmers.  The 
kingbird  or  bee  mar- 
tin, recognized  by  its 
white-tipped  black 
tail,  was  once  thought 
to  be  a  destroyer  of 
bees,  but  late  inves- 
tigations show  that 
it  eats  very  few  bees 
and  most  of  these  are 
drones.  Ninety  per 
cent  of  its  food  con- 
sists of  harmful  in- 
sects. It  nests  in 
trees  in  the  orchard 
or  forest  margin.  It 
migrates  south  in 
winter.  The  Phoebe 
or  pewee  is  a  trifle 
larger  than  the  Eng- 
lish sparrow  and  re- 
veals its  presence  by 
its  characteristic  note, 
pewit,  pewee,  phcebe, 
phoabe.  It  arrives 
from  the  south  in 
March,  and  acts  as 
special  police  to  the 
agricultural  interests 


AVES 


233 


.  267.  — Crow  and  nest,  one  tenth  natural  size.     Photographed  in  the  Academy 
of  Natural  Sciences,  Philadelphia^ 


234 


VERTEBRATA 


285 

throughout  the  summer,  when  more  than  nine  tenths  of 
its  food  consists  of  insects  and  spiders. 

Crows  (Corvidae).  — The  crows,  jays,  and  ravens  are  not 
worthy  of  much  encouragement.  The  common  crow, 
although  destroying  young  corn  and  eating  the  eggs  and 
the  young  of  other  birds,  atones  for  his  evil  deeds  by 
destroying  large  numbers  of  mice  and  cutworms.  The 
magpie  west  of  the  Rocky  Mountains  sometimes  attacks 
horses  and  mules  where  the  flesh  has  been  lacerated  by 
the  harness. 

Orioles  and  Blackbirds  (Icteridae). — The  Baltimore 
oriole  often  called  golden  robin  or  firebird  should  be  familiar 
to  every  one  in  eastern  North  America.  The  male  arriving 
from  the  south  when  the  orchards  are  in  blossom  may  be 
recognized  by  its  glossy  black  head,  throat,  wings,  and 
upper  back,  and  the  rich  orange  color  of  the  other  portions 
of  the  body.  It  is  a  trifle  smaller  and  not  so  stout  as  the 
common  robin.  The  female  is  of  a  yellowish  olive  color. 
The  nest  is  an  exquisitely  woven  pouch  swung  from  a  high 
limb. 

The  five  or  six  young  during  their  ten  days  of  life 
in  the  nest  consume  thousands  of  noxious  caterpillars  and 
canker  worms,  of  which  species  the  parents  are  also  fond. 
Beal  states  that  caterpillars  formed  thirty-four  per  cent  of 
the  food  of  one  hundred  and  thirteen  specimens  examined. 

The  bobolink,  a  country  dweller  in  eastern  North  America 
all  summer,  assists  the  farmer  in  destroying  insects,  but 
later  in  the  season  retiring  southward  it  creates  havoc  in 
the  rice  fields  and  is  known  as  the  rice  bird.  When  sold 
in  the  market  it  is  called  reed  bird.  This  species  is  an  ex- 
emplification of  the  great  difference  that  may  exist  between 


236  VERTEBRATA 

the  plumage  of  the  two  sexes  as  well  as  the  variation  in 
the  plumage  in  different  seasons.  The  black  and  white 
male  presents  a  strong  contrast  to  the  dull  yellowish-brown 
female.  In  autumn,  however,  the  plumage  of  the  male 
changes  to  the  same  hue  as  that  of  his  partner. 

The  cow  bird  never  builds  a  nest,  but  lays  its  brown- 
speckled  white  eggs  in  the  nest  of  a  smaller  bird  where 
hatching  more  quickly  and  growing  more  rapidly  than  the 
rightful  occupants,  they  crowed  the  latter  out  of  the  nest, 
It  is  nearly  as  large  as  the  robin,  but  not  so  stout.  The 
dusky  brown  female  is  smaller  than  the  male  which  has 
an  iridescent  black  head.  They  often  mingle  with  the 
cows  in  the  pasture. 

The  mead.ow  lark,  widely  distributed  over  the  United 
States,  is  a  lover  of  the  pastures  and  meadows,  where  it 
may  be  recognized  by  its  white  tail  feathers  and  large 
black  crescent  on  a  yellow  breast.  It  is  larger  than  the 
robin.  The  stomach  contents  of  ninety-three  specimens 
show  that  it  is  of  great  value  in  ridding  the  grass  lands  of 
insects.  The  blackbirds,  the  larger  of  which  are  called 
grackles,  sometimes  pull  up  the  young  corn,  but  they  make 
ample  restitution  by  destroying  weevils,  grubs,  and  army 
worms.  The  red-winged  blackbirds  nest  in  bushes  in  the 
swamps,  and  the  grackles  build  in  the  tree  tops. 

Finches  (Fringillidae). — This  family  includes  many 
small  birds  and  a  few  larger  ones,  among  which  is  the  rose- 
breasted  grosbeak,  famous  for  its  soft,  sweet,  rolling  warble 
on  moonlight  nights.  The  large  beak  and  the  rosy  breast 
of  the  male  gave  origin  to  the  name. 

The  sparrows,  of  which  there  are  more  than  a  score  of 
species  residing  with  us,  are  with  one  exception  exceedingly 


AVES 


237 


FIG.  2C9.  —  Rose-breasted  grosbeak.    Female  on  the  left  and  male  on  the  right. 
Photograph  one  fourth  natural  size. 

beneficial   birds,  consuming  large   quantities  of  noxious 

weed  seeds  and  destructive  insects. 

The  English  sparrow  (Passer  domesticus)  was  imported 
from  England  into  this  coun- 
try in  1850,  and  as  it  rears 
four  or  five  broods  of  from 
four  to  six  young  each  season, 
the  whole  country  has  become 
infested  with  the  species.  The 
male  is  easily  recognized  by 
its  black  throat  and  breast. 
In  many  localities  this  is  the 
only  sparrow  seen  in  winter. 
It  destroys  not  only  buds  and 
blossoms  but  attacks  grapes, 
berries,  tomatoes,  and  other 
FIG.  270.— Male  English  sparrow.  fruits,  in  addition  to  consum- 


238 


VERTEBRATA 


ing  large  quantities  of  grain  and  being  guilty  of  driving 
away  the  song  birds,  whose  nests  it  robs.  An  examination 
of  five  hundred  and  twenty-two  stomachs  made  by  the 
Department  of  Agriculture  showed  that  over  three  fourths 
of  the  birds  had  eaten  no  insects  whatever,  while  the  others 


FIG.  271.  —  Eggs  of  the  English  sparrow  showing  variation  in  color.      Photograph 
natural  size. 

had  devoured  but  few  insects,  most  of  which  were  beneficial 
ones.  The  nests,  untidily  built  of  hay,  stems,  and  feathers, 
in  clinging  vines  and  trees,  should  be  destroyed. 

The  chipping  sparrow,  called  chippy  or  hair  bird,  is  dis- 
tinguished from  the  English  sparrow  by  a  gray  stripe  over 
the  eye  and  a  blackish -brown  one  apparently  through  it. 
The  value  of  this  bird,  rearing  two  broods  each  season,  is 
shown  by  Weed  and  Dearborn,  who  watched  the  parent 
birds  come  to  the  nest  almost  two  hundred  times  in  one  day, 


AVES 


239 


Fio.  272.  — Nest  of  a  song  sparrow  in  a  currant  bush.    Photograph  half  natural 
size. 


bringing  caterpillars,  grasshoppers,  and  Other  insects  for 
the  young.  Forty  per  cent  of  the  food  of  the  adult  con- 
sists of  insects.  The  song  sparrow  differs  from  the  two 
preceding  in  having  the  ventral  portion  of  the  body  gray 
shading  to  white  and  heavily  streaked  with  darkest  brown. 
The  vesper  sparrow  is  easily  identified  by  the  partially 
white  outer  tail  quills  very  conspicuous  in  flight.  Its  nest 


240 


VERTEBRATA 


FIG.  273.  —Song  sparrow. 


is  built  on  the  ground  but  not 
lined  with  hair  like  the  song 
sparrow's,  which  sometimes  is 
found  in  a  bush. 

Swallows  (Hirundinidae).  — 
The  swallows  are  character- 
ized by  a  forked  tail.  They 
are  valuable  insectivorous 
birds,  seizing  their  food  on 
the  wing.  The  cliff  swallows 
and  barn  swallows  are  the 
commonest  summer  species 
in  eastern  United  States. 
The  bank  swallow  rears  its 
young  in  holes  excavated  to 
the  depth  of  two  feet  in  a  sand  bank. 

The  Chatterers  (Ampelidse).  — This  family  is  well  repre- 
sented by  the  cedar  bird,  famous  for  its  raids  on  insects. 
Seven  stomachs  examined  averaged  over  one  hundred 
canker  worms  each. 

The  Vireos  (Vireonidae). — The  vireos  are  olivaceous 
birds,  more  slender  than  the  English  sparrow.  The  red- 
eyed  and  white-eyed  are  common.  The  nest  is  easily  recog- 
nized by  the  fact  that  it  has  the  shape  of  the  lower  half 
of  a  teacup  and  is  constructed  in  the  crotch  of  a  small 
horizontal  limb  without  any  support  underneath.  During 
the  locust  pest  in  Nebraska  four  fifths  of  the  food  of  the 
red-eyed  vireo  consisted  of  these  insects. 

Wrens  and  Mocking  Birds  (Troglodytidae). — The  cat- 
bird and  house  wren  are  the  best  known  members  of  this 
family.  The  latter  is  the  most  valuable  of  all  birds  in 


AVES 


241 


FIG.  274. —Nest  of  a  chipping  sparrow  on  the  ground  in  a  wheat  field.     Photo- 
graph two  thirds  natural  size. 

destroying  insects,  and  should  be  coaxed  about  our  yards 
by  nailing  up  boxes  in  which  it  may  nest.  The  entrance 
to  a  box  must  not  be  more  than  an  inch  in  diameter,  as 
otherwise  the  English  sparrow  would  preempt  the  home. 
A  study  of  fifty-two  wrens  showed  that  ninety-eight  per 
cent  of  their  food  was  of  insects. 

Nuthatches  and  Titmouse  (Paridae).  — This  is  one  of  the 
few  families  of  birds  remaining  in  middle  and  northern 


242 


VERTEBRATA 


FIG.  276.  —  Red-eyed  vireo. 
Photograph  one  half  life 
size. 


Fm.  275.  — Cedar  bird  one  third  life  size. 
Photographed  in  Academy  of  Natural  Sci- 
ences. 

United  States  throughout  the 
winter.  The  white-breasted  nut- 
hatch seeks  its  food  running  up 
and  down  the  trees  in  summer 
and  feeds  on  seeds  in  winter.  The  black-capped  chick- 
adee or  titmouse  may  be  identified  by  its  black  crown 
and  throat.  According  to  recent  investigations  if  we 
could  persuade  enough  of  these  birds  to  dwell  with  us, 
the  plant  lice  pest,  costing  millions  of  dollars  annually, 
would  be  at  an  end.  Over  five  thousand  eggs  of  plant 
lice  have  been  found  in  the  stomach  of  one  chickadee. 
Eggs  of  other  injurious  insects,  as  well  as  the  adults,  are 
also  eaten  in  large  numbers. 

Thrushes    (Turdidae). — The  robin  is  by  many  wrong- 
fully considered  a  harmful  bird  on  account  of  the  cherries 


AVES 


243 


and  berries  taken.    The  large  number  of  cutworms,  grass- 

hoppers, and  beetles  eaten  more  than  compensates  for  the 

little     fruit     taken.      _  __  __  i 

Six  robins   shot  in 

Nebraska  contained 

two    hundred    and 

sixty-five       Rocky 

Mountain       locusts 

and         eighty-four 

other     insects. 

The  wood  thrush 
(Turdus  mustelinus) 
adds  much  to  the 
charm  of  the  wood- 
lands in  eastern 
United  States  by  the 
melody  of  its  liquid, 
flute-like  note.  It 
remains  in  the  North 
during  the  summer 
only,  while  its  relative,  the  bluebird,  a  voracious  insect 
eater,  dwells  throughout  the  year  in  the  latitude  of  New 
York  and  southward.  Meat  bones  hung  in  the  trees 
in  winter  and  small  boxes  with  inch  and  a  quarter 
entrances  nailed  up  ten  feet  above  the  ground  for 
homes  in  summer  will  do  much  toward  attracting  this 
valuable  and  beautiful  blue-backed  gem  about  the  yard. 

It  is  estimated  that  a  brood  of  five  young  during  their 
thirteen  days  of  home  life  will  consume  over  one  thou- 
sand harmful  insects,  and  more  than  half  of  the  parents' 
food  consists  of  these  injurious  creatures. 


»•  m'  ~  Nest  of  ™  s^tograph  °ne  fourth 


244 


VERTEBRATA 


FIG.  278.  —  Catbirds  and  nest.    Photographed  in  the  Academy  of  Natural  Sciences, 
Philadelphia. 


Humming  Birds  and  Swifts  (Macrochires) 

This  order  includes  the  smallest  of  birds  and  also  a  few 
larger  species.  The  most  notable  member  is  the  ruby- 
throated  humming-bird  feeding  on  the  nectar  of  flowers,  sap 
of  trees,  and  insects.  The  chimney  swift,  building  its  nest 
of  sticks  glued  together  with  saliva,  and  fixed  to  the  chim- 


AVES 


245 


ney  or  inside  of 
deserted  build- 
ings, seizes  its  in- 
sect food  in  flight, 
as  do  also  th  e  whip- 
poor-will  and 
nighlhawk,  com- 
ing forth  at  even- 
tide from  their 
forest  retreats. 

Woodpeckers 

(Pici) 


FIG.  279.  —  Wren  with  food  for  her  young.  Photo- 
graphed in  the  Academy  of  Natural  Sciences.  One 
third  life  size. 


This  order  is 
composed  of  ar- 
boreal birds,  all  of  which  with  one  exception,  the  sapsucker, 

are  preeminently 
insectivorous  birds. 
They  may  be  rec- 
ognized by  their 
habits  of  picking 
small  holes  in  the 
bark  of  trees  to  se- 
cure the  bark  bee- 
tles and  larvae  of 
other  injurious 
beetles  which  dam- 
age the  forest  trees 
to  the  extent  of 
several  millions  of 
dollars  annually. 

Fl«.  280.— White-breasted  nuthatch  photographed  in  the    rp,        j  -    ,, 

Academy  of  Natural  Sciences.    One  third  life  size.         IHC   largest  01    the 


246 


VERTEBRATA 


woodpeckers  common  near  civilization  is  the  flicker  or 
high-holer,  also  called  yellow-hammer,  easily  distinguished 
by  the  black  crescent  on  the  breast  and  the  white  rump 
conspicuous  in  flight.  It  feeds  largely  on  ants.  The 


FIG.  281.— . 


FIG.  281.  — 


FIG.  281.—  C. 


FIG.  281.  —  D. 


FIG.  281. — The  robin  demonstrating  how  quickly  hated  insects  may  be  transformed 
into  grace  and  beauty.  A  and  J3,  May  first ;  C,  May  ninth  ;  D,  May  fourteenth  ; 
E  (page  247),  May  seventeenth,  the  day  on  which  they  flew  away.  Photograph 
by  N.  F.  Davis. 


AVES 


247 


FIG.  281'.  —  E. 


hairy  woodpecker  and  the 
downy  woodpecker,  very  sim- 
ilar in  appearance,  are  the 
ones  seen  about  lawns  and 
parks.  The  red-headed 
woodpecker  nesting  in  the 
hollow  of  telegraph  poles 
and  trees  is  common  in 
many  regions. 


Cuckoos  (Coccyges) 

This  order  is  represented 
throughout  eastern    North   America   by  the    black-billed 
and  yellow-billed  cuckoos,  sometimes   called   rain  crows. 

They  are  valuable 
summer  residents 
among  the  shrub- 
bery and  in  the 
orchards  and 
woods  where  they 
devour  great  quan- 
tities of  hairy  cat- 
erpillars and  other 
insects.  During 
May  and  June,  tent 
caterpillars  consti- 
tute about  half 
their  fare.  The 
belted  kingfisher, 
common  in  most 

FIG.  282.  —  The  wood  thrush  at  her  nest.     One  fifth 

life  size.    Photograph  by  N.  F,  Davis.  parts  OI   Olir   COUU- 


248 


VERTEBRATA 


try,  is  one  of  the  few  birds  living  on  fish.     It  nests  in 
deep  holes  at  the  water's  edge. 

Hawks,  Owls,  and  Eagles  (Raptores) 

The  members  of  this  order  are  called  birds  of  prey, 
although  many  of  them  feed  largely  on  insects  and 
are  therefore  beneficial.  They  are  characterized  by  a 


FIG.  283.  — Young  bluebird  two  weeks  old  just  ready  to  fly.     Two  broods  are 
batched  yearly  in  the  cavity  of  this  old  fence  post.    Photograph  one  sixth  life  size. 


AVES 


249 


FIG.  284.  —  Ruby-throated  humming  bird  on  its  nest. 
Photographed  in  the  Academy  of  Natural  Sciences, 
Philadelphia.  Half  life  size. 


strongly  hooked  bill 

and   curved    claws, 

called  talons,  adapted 

for  seizing  and  tear- 
ing flesh.     Some  of 

them   are    of   large 

size,    such    as    the 

condor  of    South 

America     and     the 

California  vulture, 

which  are  the  largest 

birds  of  flight  in  the 

world. 

Hawks  and  Eagles 

(Falconidae)  .— 

Twenty    years    ago 

the  hawks  were  thought  to  be  man's  enemies,  and  bounties 

were  offered  in  some  states  for  their  scalps,  resulting  in 

the  paying  out  of 
many  thousands 
of  dollars  for  the 
killing  of  birds 
protecting  the 
agricultural  inter- 
ests, upon  which 
the  success  of  the 
nation  depends. 
They  feed  largely 
on  rats,  mice,  and 
other  destructive 
creatures.  Owing 


FIG.   285.  —  Chimney  swift    photographed    from    life. 
One  third  natural  size. 


VEKTEBRATA 


FIG.  286.  —  Nest  of  a  chimney  swift  built  in  a  barn.     Photograph  one  third 
natural  size. 


FlG.  287.  — Flickers  ready  for  their  first  flight.    The  hole  is  the  door  to  their  home 
Qne  tenth  life  size.    Photographed  by  Jessie  Wells. 


AVES 


251 


to  information  lately  furnished  the  lawmakers  by  the 
zoologists,  laws  have  been  passed  in  many  states  protect- 
ing all  hawks  except  the  goshawk,  Cooper's  hawk,  and  the 
sharp-shinned  hawk,  which  feed  largely  on  song  birds  and 
poultry.  The  sparrow  hawk  occasionally  destroys  a  few 


FlG.  288.  —  Black-billed  cuckoo.     Photograph  one  third  life  size. 

song  birds,  but  atones  for  it  by  preying  on  the  worth- 
less English  sparrows  and  grasshoppers.  Of  one  hundred 
and  seventy  stomachs  of  the  red-tailed  hawk  examined, 
one  hundred  and  thirty-one  contained  mice,  nine  contained 
rabbits  and  squirrels,  six  had  snakes  and  insects,  and  in 
only  four  was  any  poultry  present;  nevertheless,  this  val- 
uable bird  is  popularly  referred  to  as  the  hen  hawk. 


252  VERTEBRATA 

Only  two  species  of  eagles  dwell  in  our  land.  The  bald 
eagle,  after  attaining  the  age  of  three  years,  is  distinguished 
from  the  golden  eagle  by  its  white-feathered  head  to  which 
the  name  is  due.  The  golden  eagle  has  been  known  to 
destroy  lambs  and  young  deer,  but  the  bald  eagle  is  less 
fierce,  and  neither  has  ever  been  known  to  attack  children. 

Owls  (Bubonidse).  —  This  family  includes  all  the  owls  of 


FIG.  289.  —  Foot  of  great  horned  owl.    Photograph  half  natural  size. 

North  America  except  the  barn  owl.  With  few  exceptions 
they  are  nocturnal  birds,  living  largely  on  mice,  gophers, 
frogs,  snakes,  and  rabbits.  They  have  a  strange  habit  of 
regurgitating  out  of  the  mouth  in  the  form  of  small  pellets 
such  indigestible  portions  of  the  food  as  hair  and  bones. 
An  examination  of  these  pellets  shows  the  kinds  of  animals 
upon  which  the  bird  has  fed.  It  has  thus  been  found  that 
all  of  the  owls  with  the  exception  of  the  great  horned  owl 


AVES 


253 


are  beneficial  to  the  farmer.  The  screech  owl  and  the 
long-eared  owl,  so  called  on  account  of  the  tuft  of  feathers 
near  each  ear,  are  widely  distributed  over  the  United 


FIG.  290.— Cooper's  hawk  or  chicken  hawk  eighteen  inches  long.     Photograph  of 
a  mount  by  Neal  of  Easton. 


States.    Pellets  from  four  of  the  latter  species  showed  that 
in  fifty-nine  days  they  had  consumed  three  hundred  and 
forty-six  mice,  which  if  left  unmolested  would  have  con- 
sumed many  dollars'  worth  of  the  farmers'  produce. 
The  order  Gallince,  including  the  much  prized  game  birds, 


254 


VERTEBBATA 


partridge,  grouse,  and  turkey,  and  the  order  Columbce,  com- 
posed of  the  doves,  will  not  be  discussed,  as  their  repre- 
sentatives are  scarce  in  most  localities. 


The   Herons    (Herodiones) 

This  order  includes  the  herons,  storks,  and  ibises,  which 
have  long  necks  and  long  legs  for  wading.    They  are  shore- 


FlO.  291.  —  Sharp-shinned  hawk  one  foot  long.    Photograph  of  a  mount 
by  Neal. 

loving  birds  feeding  upon  frogs  and  fish.  The  great  blue 
heron,  wrongly  called  crane,  is  common  in  eastern  North 
America,  where  it  may  be  seen  wading  about  in  the  meadows 
and  swamps.  In  nesting,  the  herons  usually  form  societies, 
so  that  in  the  space  of  two  or  three  acres  one  may  count  in 


AVES 


255 


the  trees  more  than  a  hundred  nests.  The  little  blue  heron 
visits  the  creeks  east  of  the  Mississippi  River.  The  snowy 
heron  or  snowy  egret  is  the  most  beautiful  bird  in  the  world. 
Its  head  and  back  bear 
numerous  filmy  plumes 
which  are  so  much  sought 
after  to  adorn  the  head 
gear  of  women  that  the 
species  once  so  abundant 
in  Florida  is  now  almost 
exterminated.  A  law  has 
lately  been  passed  pre- 
venting the  sale  of  these 
plumes  known  as  aigrettes. 
That  some  effective  means 
to  stop  the  use  of  song  bird 
plumage  in  millinery  work 
should  be  devised  is  evi- 
dent when  we  consider  the 
number  of  birds  annually 
sacrificed  on  the  altar  of 
woman's  vanity.  Forest 
and  Stream  mentions  a 
dealer  who  in  three  months 
supplied  over  eleven  thou- 
sand skins  for  the  milliners,  and  the  same  person  is  said 
to  handle  thirty  thousand  birdskins  every  year.  A  single 
foreign  order  given  a  New  York  milliner  called  for  the 
death  of  over  forty  thousand  of  our  beautiful  birds,  which 
were  sold  at  ten  cents  each.  During  four  months  seventy 
thousand  birdskins  were  sent  from  one  Long  Island  vil- 


FIG.  292-  — Sparrow  hawk  ten  inches 
long.    Photograph  from  life. 


256 


VERTEBBATA 


FlG.  293.  —  Red-sliouldered  hawk  at  her  nest  in  the  tree  top.     Photographed  in  the 
Academy  of  Natural  Sciences,  Philadelphia.     One  eighth  life  size. 

lage  to  supply  the  peacock  populace  of  New  York.  The 
Audubon  Society  has  proved  itself  a  mighty  force  for  good 
not  only  in  showing  the  evil  wrought  by  collectors  of  birds 
and  their  eggs,  but  also  in  rendering  unpopular  the  use  of 
birds  for  millinery  purposes.  If  every  pupil  will  do  his  part 
in  that  great  missionary  work  of  protecting  the  birds,  their 
nests,  and  young,  in  the  coming  years  the  dream  of  Shelley 
may  be  nearer  realization. 


AYES 


25? 


' { No  longer  now  the  winged  habitants 
That  in  the  woods  their  sweet  lives  sing  away 
Flee  from  the  form  of  man ;  but  gather  round, 
And  prune  their  sunny  feathers  on  the  hands 
Which  little  children  stretch  in  friendly  sport 
Toward  these  dreadless  partners  of  their  play. 

.  .  .  Happiness 
And  science  dawn,  though  late,  upon  earth." 


FIG.  294.  —  Our  national  bird,  the  bald  eagle.     Photograph 
of  a  mount  by  Neal.    One  sixth  life  size. 


258 


VERTEBRATA 


That  birds  limit  in  a  large  degree  the  outbreaks  of  injuri- 
ous animals  is  shown  by  recent  reports.  An  apple  orchard 
in  Illinois  was  severely  attacked  by  canker  worms  (Fig.  88) 
and  numerous  species  of  birds  came  to  feed  on  the  pests. 
Several  individuals  of  each  of  thirty-six  different  species 
were  killed  and  the  stomach  contents  examined  by  Pro- 


FiG.  295.  —  A,  Screech  owl.     Photograph  from  life.     One  fifth  natural  size. 
M,  Long-eared  owl. 

fessor  Forbes.  Canker  worms  made  up  twenty  per  cent  of 
the  food  of  the  robins,  fifteen  per  cent  of  the  food  of  cat- 
birds, two  thirds  of  the  food  of  the  warblers,  forty  per 
cent  of  the  food  of  the  vireos,  fifty-nine  per  cent  of  the 
food  of  the  indigo  bunting,  sixty-one  per  cent  of  the  food 
of  the  chickadees,  seventy-five  per  cent  of  the  food  of  the 
black-billed  cuckoos,  and  practically  all  of  the  food  of 
the  cedar  birds. 


AVES 


259 


Similar  striking  facts  are  shown  by  Aughey's  investiga- 
tion during  the  outbreak  of  the  Rocky  Mountain  locust, 
when  in  a  single  year,  1874,  they  destroyed  forty-five  mil- 
lions of  dollars'  worth  of  crops.  For  one  meal,  six  robins 
had  eaten  two  hundred  and  sixty-five  locusts;  five  catbirds, 


FIG.  296.  —  A  friend  of  the  birds. 

one  hundred  and  fifty-two;  three  bluebirds,  sixty-seven; 
nine  chickadees,  four  hundred  and  eighty-one;  twenty 
swallows,  five  hundred  and  sixty-five:  and  eight  flickers, 
two  hundred  and  fifty-two.  Every  species,  of  which  there 
were  fifty  present  in  that  region,  fed  on  the  pests.  Out- 
breaks of  army  worms  and  field  mice  have  also  been  checked 
by  the  birds  in  a  similar  manner. 

The  pupils  of  every  school  should  determine  whether 
the  number  of  birds  is  increasing  or  decreasing  from  year 


260  VERTEBRATA 

to  year.  An  excellent  method  of  determining  this  is  to 
count  the  nests  to  be  seen  in  the  trees  as  soon  as  the  leaves 
have  fallen.  Robins  and  some  other  birds  use  the  same 
nest  for  two  or  even  three  broods  in  one  year,  but  on  an 
average  it  is  safe  to  count  only  five  birds  reared  from  each 
nest.  Small  boys  and  cats  are  the  greatest  enemies  of 
young  birds  near  towns  and  cities. 

The  migration  of  birds  is  worthy  of  the  attention  of  every 
one.  In  the  latitude  of  New  York,  the  chief  birds  remain- 
ing with  us  throughout  the  year  are  the  owls,  crows,  wood- 
peckers, cedar  birds,  song  sparrow,  English  sparrow, 
black-capped  chickadee,  and  bluebird.  Some  of  these 
frequently  go  south  during  severe  cold  weather.  The 
other  summer  residents  pass  the  winter  in  the  South, 
some,  like  the  bobolinks,  going  as  far  as  Brazil. 

In  many  cases  the  migration  trips  are  made  by  night 
and  often  at  a  great  height.  The  purple  martin,  the 
kingbird,  the  swallows,  and  the  orioles  depart  in  September, 
and  the  majority  begin  their  southern  journey  in  October; 
but  the  bluebird,  robin,  and  chipping  sparrow  remain 
until  November  and  return  as  early  as  March.  The 
latest  comers  in  spring  are  the  wood  thrush,  vireos,  orioles, 
bobolinks,  and  cuckoos,  which  arrive  in  May.  The  cause 
of  bird  migration  is  not  known.  Cold  weather  may  seem 
to  force  them  south,  but  why  do  they  leave  the  warm 
tropical  regions  abounding  in  food  in  the  spring  and  come 
to  the  bleak  north? 

The  regions  to  which  some  of  our  species  go  for  winter- 
ing are  quite  definitely  mapped  out.  The  robins  that 
spend  the  summer  in  Canada  have  for  their  winter  resi- 
dence portions  of  the  United  States  in  the  latitude  of 


MAMMALIA  261 

Washington,  while  the  robins  summering  in  northern 
United  States  migrate  to  a  winter  home  along  the  Gulf  of 
Mexico.  The  nighthawks,  living  in  Alaska  from  May  to 
September,  fly  over  five  thousand  miles  to  their  congenial 
winter  home  in  Patagonia.  Over  fifty  species  of  New 
England  birds  winter  in  South  America.  Twenty-five 
species  from  northern  United  States  pass  the  winter  in 
Porto  Rico,  an  equal  number  go  to  Cuba,  and  at  least 
twenty  species  remain  during  our  cold  season,  in  Jamaica. 
Others,  such  as  the  red-eyed  vireo,  migrate  to  Central 
America. 

Every  school  should  keep  a  record  of  the  time  of  the 
appearance  of  each  species  in  the  spring  and  its  departure 
in  the  autumn.  The  pupils  should  be  encouraged  to 
report  how  many  birds  they  have  coaxed  to  dwell  in  the 
yard  and  garden  by  putting  out  meat  bones  and  bread 
crumbs  in  winter,  and  erecting  nesting  boxes  for  summer. 

19.    MAMMALIA 

The  mammals  are  distinguished  from  all  other  verte- 
brates by  their  habit  of  providing  the  young  with  milk 
and  by  the  possession  usually  of  a  hairy  covering.  Like 
the  birds  they  are  distributed  throughout  both  the  warm 
and  cold  regions  of  both  hemispheres.  Since  the  habits  as 
well  as  the  structure  of  the  different  groups  vary  widely 
it  will  be  necessary  to  consider  the  characteristics  of  each 
of  the  eleven  orders. 

Egg  layers  (Monotremata). — The  duck  mole  of  Aus- 
tralia is  one  of  the  three  species  of  mammals  which  lay 
eggs.  It  deposits  hi  its  burrow  on  the  bank  of  a  stream 


262  VERTEBRATA 


FIG.  297.  —  The  duck  mole  or  duck  bill.    Photograph  one  fourth  natural  size. 

two  eggs  about  as  large  as  those  of  a  robin.  The  Echidnas, 
of  which  there  are  two  species,  inhabit  Australia  and  New 
Guinea.  The  single  egg  deposited  is  placed  in  the  abclomi- 


FIG.  298.  — Kangaroos.    Thejone  at  the  left  shows  the  opening  to  the  pouch. 


MAMMALIA 


263 


nal  pouch  where  the  young  one,  soon  hatching,  is  carried 
for  some  weeks. 

Pouched  Mammals  (Marsupialia  or  Didelphia). — The 
marsupials,  though 
not  oviparous ,  ap- 
proach that  condi- 
tion inasmuch  as  the 
young  are  born  in  a 
very  immature  condi- 
tion and  in  most  cases 
are  carried  in  the 
pouch  by  the  female 
several  weeks.  The 
largest  species  of  the 
kangaroos  dwelling  in  Australia  is  the  boomer,  standing  four 
feet  high  and  capable  of  clearing  twenty  feet  at  a  single 
bound.  The  opossums  are  the  only  marsupials  living  in 
North  America.  The  one  representative  in  the  United 


FIG.  299.  —  Virginia    opossum.    Photograph    by 
N.  F.  Davis.    One  eighth  life  size. 


FIG.  300.  —  The  spiny  ant-eater  (Kchidna).     Photograph  one  fourth  life  size. 


264  VERTEBRATA 

States  is  the  Virginia  opossum  found  in  nearly  every 
state.  The  young  varying  in  number  from  six  to  twelve 
are  naked,  blind,  and  about  half  an  inch  long  at  birth, 
when  the  mother  by  means  of  her  fore  paws  places  them 
in  her  pouch.  Here  they  remain  several  weeks  constantly 
attached  to  the  teats  through  which  the  mother  pumps 
the  milk  into  their  mouths. 

Ant-eaters  (Edentata).  —  This  order  is  so  named  be- 
cause some  of  the  species  have  no  teeth.  The  armadillos, 
remarkable  for  their  covering  of  bony  plates,  inhabit 
South  America  and  southern  North  America,  while  the 
ant-eaters  dwell  in  South  America,  Asia,  and  Africa. 
The  Sloths  live  in  South  America  only. 

Sea  cows  (Sirenia). — The  members  of  this  order  are 
characterized  by  the  absence  of  hind  limbs  and  the  pres- 
ence of  paddle-like  fore  limbs  adapted  for  an  aquatic  life. 
The  manatee  is  the  only  representative  in  our  country. 
It  swims  in  the  rivers  of  Florida.  The  fact  that  the  flipper- 
like  fore  limbs  contain  the  same  bones  present  in  the  ter- 
restrial mammals,  indicates  that  the  ancestors  of  the 
Sirenia  were  land  mammals. 

Whales,  Dolphins,  and  Porpoises  (Cetacea).  —  These,  like 
the  Sirenia,  are  entirely  aquatic,  and  with  few  exceptions 
live  in  salt  water  only.  They  are  characterized  by  the 
absence  of  hair  and  hind  limbs,  though  in  some  species 
rudiments  of  the  latter  are  found  beneath  the  skin,  indi- 
cating that  the  whales  have  descended  from  land  animals 
with  two  pairs  of  limbs.  The  toothless,  or  baleen  whales, 
are  valuable  both  for  oil  and  whalebone.  The  largest 
species,  the  sulphur-bottom  whale  of  the  Pacific,  attains  a 
length  of  ninety-five  feet,  One  individual  will  yield  three 


MAMMALIA 


265 


hundred  barrels  of  oil  and  two  tons  of  whalebone,    The 
toothed  or  sperm  whales  inhabit  both  the  great  oceans. 
The  dolphins  occur  in  schools  and 
dart  out  and  in  the  water  at  fre- 
quent intervals.    The  common  At- 
lantic porpoise   is  the  puffer  seen 
rolling  in    the   breakers  near    the 
shore. 

Hoofed  Mammals  (Ungulata).  — 
The  members  of  this  order  are  nota- 
ble for  the  variation  in  the  number 
of  digits  (toes  or  ringers)  from  one 
to  five.  The  horses  are  one-toed; 
the  cattle  and  deer,  two-toed;  the 
pigs,  four-toed;  and  the  elephant, 
five-toed.  This  condition  is  ex- 
plained by  the  theory  of  evolution, 
declaring  that  all  ungulates  origi- 
nally had  five  digits  to  each  limb, 
but  in  some  cases  one  or  more  has 
been  lost  because  they  were  not  of 
advantage  to  the  species.  The  an- 
cestors of  the  horse  known  by  fossil 
remains  exhibit  four  complete  toes, 
and  the  most  ancient  mammals,  liv- 
ing several  millions  of  years  ago,  all 
had  five  toes  on  each  limb.  Rudi- 
ments of  these  lost  digits  are  present 
in  the  horse,  deer,  and  cow.  The  digits  are  numbered 
from  the  inside  outward,  i.e.,  from  the  thumb  toward  the 
little  finger.  The  horse  walks  on  the  end  of  the  third 


FIG.  301.  —  Skeleton  of  a 
liorsc  that  lived  in  Colo- 
rado more  than  a  million  of 
years  ago.  From  Guide 
Leaflet  of  the  American 
Museum  by  Matthews. 


266 


VERTEBRATA 


digit,  so  that  the  wrist  and  ankle,  often  wrongly  called 
the  knee,  are  more  than  a  foot  above  the  ground,  while 
the  real  knee  is  close  up  to  the  body.  Animals  walking 
on  the  ends  of  their  toes  are  said  to  be  digitigrade,  in 


PlG.  302.  -~  Skeleton  of  the  horse,  a,  rudiment  of  the  fourth  digit  (splint  bone) 
about  half  as  long  as  the  third  ;  rf,  second  digit ;  e,  ankle ;  wt  wrist ;  n,  knee  ; 
m,  femur  ;  /,  forearm  with  large  radius  and  rudimentary  ulna  ;  h,  humerus. 


distinction  to  those  walking  on  the  flat  of  the  foot,  called 
plantigrade. 

The  cattle  family  (Bovidce]  includes  the  goats,  sheep,  and 
cows,  among  the  most  celebrated  of  which  are  the  American 
bison  (buffalo)  now  nearly  extinct,  and  the  Rocky  Moun- 
tain goat  able  to  walk  on  almost  perpendicular  cliffs. 


MAMMALIA 


267 


The  deer  family  (Cervidce)  is  well  represented  on  all  the 
continents  except  Africa.  With  the  exception  of  the 
caribou  only  the  males  of  the  deer  possess  antlers,  and  they 
are  always  shed  annually,  and  usually  in  February  or  March. 
A  new  growth  be- 
gins at  once  and 
continues  so  rap- 
idly that  antlers 
like  those  of  the 
elk  measuring  four 
feet  are  renewed 
in  less  than  four 
months.  The  elk, 
the  largest  species 
of  the  round- 
horned  deer, 
abounds  in  the 

vicinitv  Of  the  Yel-        FIG.  30S.  — Kocky    Mountain    goat.    Photographed 
Uiy  °  in  the  Philadelphia  Zoological  Gardens. 

lowstone    Park. 

The  Virginia  deer,  also  called  white-tailed  deer,  inhabits 
every  state  in  the  Union  except  Delaware,  Oregon,  Nevada, 
California,  and  Arizona,  but  is  most  abundant  in  the 
Adirondacks,  Maine,  Vermont,  and  Michigan. 

The  moose,  the  largest  species  of  the  deer  family,  reaches 
a  height  of  nine  feet.  The  overhanging  nose,  high-humped 
shoulders,  and  huge  flat  antlers  of  the  male  distinguish  it 
from  the  other  deer.  It  is  found  in  northern  United 
States,  Canada,  and  Alaska.  The  caribou  or  reindeer,  both 
sexes  of  which  bear  slightly  flattened  antlers,  occupy  the 
upper  half  of  the  continents  of  North  America  and  Eurasia, 
where  they  feed  upon  moss  and  lichens.  The  domestic 


268  VERTEBRATA 

reindeer  (Rangifer  tarandus)  is  a  native  of  Siberia  whence 
over  fifteen  hundred  animals  have  been  imported  into 
Alaska  since  1892,  and  they  have  multiplied  to  the  number 
of  several  thousand.  During  the  last  few  years  the  United 
States  Government  has  granted  annually  twenty-five 


FIG.  304.  —  Skull  of  a  deer  with  the  lower  jaw  removed.  The  burr  at  the  base  of 
the  antler  shows  where  it  separates.  The  absence  of  upper  incisors  and 
canine  teeth  is  characteristic  of  ruminants  (cud  chewers). 

thousand  dollars  for  the  purpose  of  making  the  reindeer 
a  permanent  resource  for  food  and  domestic  service  among 
the  Eskimos. 

The  camel  of  Africa,  the  'llama  of  South  America,  and 
the  elephant  of  Africa  and  Asia  have  been  trained  to  render 
valuable  service  to  man .  The  water  sacs,  which  are  numer- 


MAMMALIA  269 

ous  pouches  on  the  wall  of  the  stomach,  enable  the  camel 
to  go  many  hours  without  water  in  the  sandy  Sahara.  The 
tusks  of  the  elephant  are  the  two  upper  overgrown  incisor 


FIG.  305.  —  Wapiti  or  American  elk.    Photographed  in  the  Philadelphia  Zoological 
Gardens. 

teeth  composed  almost  entirely  of  dentine,  which  furnishes 
the  ivory  of  commerce. 

Gnawers  (Rodentia). — Any  one  of  the  four  hundred 
species  of  rodents  living  in  America  may  be  recognized  by 
the  large  chisel-shaped  incisor  teeth,  of  which  there  are  two 
in  the  lower  jaw  and  either  two  or  four  in  the  upper  one, 
while  the  canine  teeth  are  wanting  (Fig.  309). 


270 


VERTEBRATA 


The  squirrels  (Sciuridce)  are  represented  by  the  chip- 
munks or  ground-squirrels,  usually  striped,  the  red  squirrel 
living  in  northeastern  United  States,  and  the  gray  squirrel 

inhabiting  the  for- 
ests east  of  the 
Rocky  Mountains. 
The  red  squirrel 
deserves  to  be  ex- 
terminated, as  it 
drives  away  the 
gray  squirrel  and 
destroys  the  eggs 
and  young  of  the 
song  birds.  The 
marmots  are  bur- 
rowing rodents 
much  larger  than 
the  true  squirrels. 
The  woodchuck  (Marmota  monax)  abounds  nearly  every- 
where east  of  the  Rockies.  Instead  of  storing  up  food 
like  the  squirrels  it  hibernates  during  the  cold  season,  and 
when  removed  from  its  burrow  in  winter  appears  to  be  in 
an  unconscious  condition.  The  heart  beats  but  a  few 
times  per  minute  and  respiration  is  very  slow,  so  that  the 
food  stored  up  largely  in  the  form  of  fat  in  its  own  body 
enables  it  to  pass  the  cold  season  without  eating.  The 
prairie  dog,  ranging  from  Texas  to  Canada,  is  a  social 
animal  dwelling  in  large  colonies  sometimes  more  than 
fifty  miles  in  length. 

The  rats  and  mice  (Muridce)  number  about  one  hundred 
<and  seventy-five  species  in  North  America.  The  muskrat 


FIG.  306. — A  moose  pushing  its  way  through  the 
underbrush. 


MAMMALIA 


271 


is  aquatic  in  habit,  dwelling  in  holes  along  the  banks  of 
streams.  The  brown  rat  (Mus  dccumanus)  has  spread 
from  its  original  home  in  western  China  throughout  the 
whole  civilized  world.  About  1730  it  migrated  into 
Russia,  appeared  in  Paris  in  1750,  was  introduced  into 


FIG.  307.  —Camel.    Photographed  in  the  Philadelphia  Zoological  Gardens. 

America  along  the  Atlantic  coast  in  1775,  and  by  1850 
had  spread  to  the  Pacific  coast.  It  destroys  young  poultry, 
eggs,  and  grain.  Like  the  house  mouse,  it  multiplies 
rapidly,  producing  three  or  four  litters  annually  of  from 
five  to  ten  each. 

The  hares  and  rabbits  (Leporidce)  are  widely  distributed. 
The  former  have  long  ears  and  long  legs,  while  in  the  latter 


272 


VERTEBllATA 


these  organs  are  comparatively  short.  Rabbits  intro- 
duced into  countries  where  their  natural  enemies,  hawks, 
owls,  eagles,  and  carnivorous  mammals  are  not  sufficiently 
abundant  to  keep  them  in  check,  have  become  great  pests. 
In  Australia  they  devoured  the  grass  to  such  an  extent 


FIG.  3U8.  —  Photograph,  of  the  elephant  showing  the  exte 
the  trunk. 


al  nares  at  the  end  of 


that  thousands  of  sheep  starved  to  death.  Fifteen  million 
skins  were  exported  from  New  South  Wales  in  one  year. 
In  some  places  the  government  has  erected  fences  of  wire 
netting  to  keep  the  pests  from  destroying  the  crops.  Since 
the  killing  off  of  the  coyotes  and  wolves  in  western  United 
States,  the  jack  rabbits  have  increased  enormously,  so 


MAMMALIA 


273 


that  at  intervals 
" drives"  are  held. 
On  these  occasions 
as  many  as  twenty 
thousand  animals 
are  slain  in  one 
day. 

Bats  and  Flying- 
Foxes  (Chiroptera). 
—  Unlike  most  of 
the  rodents,  the 
greater  number  of 
the  chiroptera  are 
beneficial  on  ac- 
count of  the  harm- 
ful insects  they 

destroy.     They  are  nocturnal  and  spend  the  day  in  caves 
and  forests.     The  bones  of  the  fingers  are  much  extended 


FIG.  309.  —  Woodchuck  or  ground  hog.    Photograph 
one  fourth  life  size. 


FIG.  310.  —  The  red  bat  photographed  from  beneath.    Half  life  size. 


274 


VERTEBRATA 


so  as  to  subtend  the  large  membrane  stretching  from  the 
hind  limb,  thus  affording  the  means  of  flight.  Among 
the  insect  eaters  occurring  in  our  land  are  the  red  bat  and 
brown  bat  flitting  through  the  air  at  twilight.  The  fruit 
eaters  or  flying  foxes,  including  some  species  with  a  wing- 
spread  of  three  feet,  inhabit  southeastern  Asia  and  adja- 
cent islands.  The  vampire  bats  are  confined  to  Central 


FIG.  311.  — Short-tailed  shrew 


o  thirds  life  size. 


America  and  South  America  and  the  West  India  Islands. 
While  a  few  of  them,  such  as  the  Javelin  bat,  suck  the 
blood  from  horses  and  cattle  and  even  attack  man,  the 
majority  are  insect  or  fruit  eaters. 

Insect  Eaters  (Insectivora). — -Although  members  of 
this  order  are  common  in  every  state,  but  few  people  have 
seen  them,  because  they  pass  their  lives  in  underground 
burrows  seeking  insects  and  earthworms.  As  their  eyes 
are  of  no  use  in  the  dark,  they  have  become  rudimentary 


MAMMALIA 


275 


in  many  species  and  appear  as  mere  dark  spots.  The 
shrews,  numbering  thirty-five  species,  are  characterized  by 
a  pointed  nose  and  small  feet,  while  the  moles  have  ex- 
tremely large  fore  feet  enabling  them  to  excavate  rapidly 
the  tunnels  whose  elevated  roofs  form  serpentine  figures 
over  the  lawns.  The  hedgehogs,  distributed  throughout 


Fio.  312.  — Wild  cat  (Lynx  rufus).     Photographed  in  the  American  Museum  of 
Natural  History. 

Europe,  Africa,  Asia,  and  some  of  the  adjacent  islands,  are 
covered  on  the  upper  surface  with  an  armature  of  spines, 
and  possess  the  power  of  rolling  themselves  up  into  the 
form  of  a  ball. 

Flesh  Eaters  (Carnivora). — Nearly  a  hundred  species 
belonging  to  this  order  dwell  in  North  America.  Their 
distinguishing  features  are  large  canine  teeth,  flesh-cutting 


276  VERTEBRATA 

molars,  and  clawed  toes.  The  cats  (Felidce)  are  repre- 
sented in  this  country  by  the  jaguar  of  Texas,  the  puma  or 
mountain  lion  of  the  western  states,  Adirondacks,  and 
Florida,  and  the  bay  lynx,  called  wildcat  or  catamount, 


B*IG.  313.  —  Red  foxes  at  the  entrance  to  their  underground  home.     Photographed 
in  the  American  Museum  of  Natural  History. 

inhabiting  the  thickets  of  nearly  all  the  states  east  of  the 
Mississippi. 

The  domestic  cat  is  thought  to  be  a  descendant  of  the 
Egyptian  cat  (Felis  caffra)  widely  distributed  in  Africa. 
The  lion  and  tiger,  dwelling  in  the  Old  World,  are  the  most 
formidable  of  the  tribe.  In  India  the  tiger  is  said  to 
destroy  twenty  thousand  cattle  annually.  Certain  indi- 


MAMMALIA 


277 


viduals  acquiring  a  love  for  human  flesh  are  known  as  man- 
eaters.  To  these,  several  hundred  of  the  natives  of  India 
fall  victims  every  year. 

The  dogs  (Canidce)  include  the  wolves  and  foxes.  The 
coyote  and  prairie  wolf  breed  hi  the  rocky  caverns  and 
washouts  of  the  Rocky  Mountain  region  and  the  great 


FlG.  314.  — The  Weasel  (Putorius  erminea)  in  winter.    One  fourth  natural  size. 

plains,  and  make  life  uncertain  for  the  cattle,  sheep,  and 
poultry.  A  study  of  structure  and  habits  makes  it  evident 
that  many  of  the  one  hundred  and  fifty  varieties  of  our 
domestic  dog  (Canis  familiaris)  originated  from  wolves, 
wliile  it  is  probable  that  others  are  descendants  of  jackals. 
The  foxes,  of  which  there  are  four  species  hi  our  country, 
are  much  valued  for  their  fur.  The  red  fox  (Vulpes  ful- 
vous), widely  distributed  east  of  the  Mississippi,  exhibits 


278  VERTEBRATA 

a  remarkable  variation  in  the  color  of  its  fur.  While  ordi- 
narily of  a  reddish  hue  it  occasionally  varies  to  a  jet  black. 
The  red  skin  is  valued  at  only  one  or  two  dollars,  but  a 
black  one  sometimes  sells  for  as  much  as  two  thousand 


FIG.  315.—  Polar  bear  (Thalarctosmaritimus).    Photographed  in  the  Philadelphia 
Zoological  Gardens. 

dollars.    The  gray  fox  is  confined  to  the  more  southern 
portions  of  the  United  States. 

The  marten  family  (Muslelidce)  includes  the  fish-loving 
otter,  slender-bodied  mink  and  weasel,  the  marten,  skunk, 
and  badger,  all  of  which  are  valuable  fur-bearing  animals. 
The  weasel  and  mink  are  destructive  to  poultry,  but  the 
weasel  atones  for  his  evil  by  terrorizing  the  rats  and  mice. 


MAMMALIA 


279 


Like  many  other  creatures  in  the  north  the  weasel  changes 
from  brown  to  white  in  winter.  The  source  of  the  white 
ermine  is  the  stoat  or  ermine  occupying  the  northern  part 
of  both  hemispheres. 

The  bears  ( Ursidce)  are  represented  in  our  country  by 
four  species,  of  which  the  black  bear  ( Ursus  americanus) 
has  the  widest  range.  It  is  found  in  many  of  the  forests 


FIG.  316.  —  The  California  sea  lion  (Zalophus  calif omianus).    Photographed  in  the 
Philadelphia  Zoological  Gardens. 

from  Florida  to  Alaska.  The  color  varies  frequently  to  a 
brown  in  the  western  states,  where  it  is  called  the  cinnamon 
bear.  The  large  grizzly  bear  of  the  Rockies  is  said  to  have 
killed  and  maimed  more  hunters  than  all  the  other  bears 
of  the  world  combined.  The  polar  bear  inhabits  the  coast 
of  the  Arctic  Ocean,  where  it  feeds  upon  fish  and  seals. 

The  Pinnipedia  include  those  carnivora  whose  limbs  are 
adapted  for  swimming.  They  are  the  sea  lions,  seals,  and 
walruses.  The  large  canines  forming  the  long  ivory  tusks 
in  the  upper  jaw  distinguish  the  walrus  from  the  other  two 


280 


VERTEBKATA 


groups.  The  sea  lions  resemble  the  seals,  but  have  no 
external  ears  and  no  hair  or  claws  on  the  front  flippers. 
The  neck  of  the  sea  lion  is  much  longer  than  that  of  the  seal. 
Sealskin  fur  is  not  derived  from  a  seal,  but  from  the  sea 
lion  (Callolaria  ursina),  breeding  only  in  the  region  of  the 
Behring  Sea,  although  making  circuits  in  winter  as  far 
south  as  San  Francisco. 
Primates.  —  This  order  includes  the  lemurs,  monkeys, 


FIG.  317.  —  Skull  of  man  on  the  right  and  young  chimpanzee  on  the  left.    Photograph. 

and  man,  all  of  which  have  hands  and  handlike  feet,  and 
in  most  cases  the  thumb  is  opposable  to  the  fingers,  so  as 
to  grasp  a  limb.  The  lemurs  of  Madagascar  are  the  lowest 
Primates,  and  with  the  exception  of  their  grasping  hands 
and  feet  resemble  externally  some  of  the  Carnivora.  The 
common  black  and  white  lemur  is  about  as  large  as  a  cat. 
About  twenty  species  of  monkeys  of  a  low  order  extending 
from  Mexico  to  Brazil  are  included  in  one  family,  the 
marmosets.  They  are  all  small,  but  few  being  larger  than 
squirrels,  and  are  characterized  by  toes  with  pointed  claws, 


MAMMALIA 


281 


a  nonopposable  thumb,  and  the  absence  of  wisdom  teeth. 
The  Neiv  World  monkeys  are  marked  by  a  flattened  nose 
with  the  nostrils  separated  by  a  broad  septum.  They 
range  from  Mexico  to  Brazil.  Many  of  them  have  pre- 
hensile tails  with  which  they  are  able  to  support  themselves 
from  the  limbs  of  trees. 

The  best  known  groups  of  the  Old  World  monkeys  are  the 
baboons,  apes,  and  gibbons.  The  baboons  have  long, 
doglike  noses  and 
live  only  in  Af- 
rica. They  travel 
in  troops  of  a  dozen 
or  more,  robbing 
grain  fields  and 
fighting  fiercely 
when  attacked. 

The  anthropoid 
apes  (Simiidce),  of 
which  there  are 
about  ten  species, 
include  those  mon- 
keys having  no 
tails  and  for  the 
mosL  part  bearing 
a  striking  resem- 
blance in  structure 
to  man.  The  gib- 
bons are  of  small 
size,  slender  pro- 
portions, and  of  low  intellect.  They  inhabit  Borneo,  Su- 
matra, the  Malay  Peninsula,  and  Siam,  The  gorilla  (Gor- 


FIG.  318.  —  Gorilla  shot  and  photographed  in  West 
Africa.  By  permission  of  the  Academy  of  Natural 
Sciences. 


282 


VERTEBRATA 


ilia  gorilla)  is  the  largest,  fiercest,  and  most  manlike  of  the 
apes.  It  is  the  only  one  which  walks  erect  without  being 
taught,  and  in  its  home  land  along  the  equator  of  Africa 
it  is  said  to  spend  much  time  on  the  ground.  It  does  not 
thrive  in  captivity.  Only  one  live  specimen  has  ever 
arrived  in  the  United  States. 

The  chimpanzee,  half  as  large  as  the  gorilla,  has  brain, 
face,  ears,  and  hands  more  manlike  than  those  of  any  other 
ape,  and  is  the  most  intelligent  of  the  group.  Sally  of  the 


FIG.  319.  —  Photograph  of  a  chimpanzee. 

London  Zoo  could  count  up  to  five.  Its  home  is  in  the 
dense  forests  of  equatorial  Africa.  The  orang-outang, 
about  two  thirds  as  large  as  the  gorilla,  may  be  distinguished 
from  the  black-haired  chimpanzee  by  its  reddish  hair, 


MAMMALIA 


288 


brown  skin,  and  small  ears.  It  manifests  an  intelligence 
almost  equal  to  the  chimpanzee.  The  young  are  readily 
trained  to  sit  at  a  table,  eat  with  a  spoon,  drink  from  a 
cup,  and  give  other  performances.  It  lives  in  Borneo  and 
Sumatra. 

Structure  of  a  Mammal.  —  The  structure  of  a  mammal 
may  be  understood  by  dissecting  any  one  of  the  smaller 
forms,  such  as  the  rat,  guinea  pig,  rabbit,  or  cat.  Although 


FIG.  320.  —  Side  view  of  the  muscles  of  the  cat's  body.  An  irregular  rectangular 
piece  has  heen  cut  from  each  of  the  tAvo  large  side  muscles  and  the  two  limbs 
have  been  cut  off  near'the  middle  showing  the  bones  white.  From  Davison's 
"  Mammalian  Anatomy." 

the  description  here  given  applies  specially  to  the  cat, 
yet  any  of  the  other  species  named  may  be  used,  as  the 
structure  of  all  is  practically  the  same.  The  animal  can 
be  painlessly  killed  in  twenty  minutes  by  placing  it  in  a 
small,  tight  box  or  tin  can  containing  a  cloth  or  piece  of 
cotton  wet  with  an  ounce  of  chloroform  or  ether. 

The  skin  should  be  removed  by  making  a  slit  in  it  along 
the  median  ventral  line  and  by  pulling  the  cut  edge  outward 


284 


VERTEBRATA 


hu 


and  severing  the  white 
fibrous  connective  tissue 
uniting  the  skin  to  the 
muscles.  Many  of  the 
five  hundred  muscles 
forming  the  flesh  are  seen 
to  be  composed  of  three 
parts.  The  white  glisten- 
ing part  usually  connect- 
ing the  muscle  at  either 
end  with  the  bone  is  the 
tendon,  and  the  larger 
middle  portion  is  called 
the  belly.  In  many  cases 
the  muscle  fibers  are  at- 
tached directly  to  the 
bone  without  any  inter- 
vening tendon.  The  na- 
ture of  the  thousands 
of  striated  muscle  fibers 
forming  the  muscle  is 
easily  demonstrated  by 
tearing  into  minute  shreds 
with  two  sharp  needles 
a  bit  of  muscle  placed  in 
a  little  water  or  alcohol 
on  a  glass  slide,  and  then 
examining  it  under  the 

FIG.  321.  — Muscles  on  the  outer  side  of  the  high    power  of  the  micro- 
cat's  fore  limb.    A  piece  has  been  cut  from  »  I 

the  triceps.    The  white  cords  in  the  region  of  SCOpe.          A      COVer      glaSS 

the  foot  are  tendons;  an,  a  ligamentous  band.  oVi^l^     U«    r»lar^rl    rm     tV»o 

From  Davison's"  Mammalian  Anatomy."  SnOUlCL    D6    plated   On    me 


MAMMALIA 


285 


specimen  and  care  taken  that  there  is  sufficient  liquid 
to  fill  the  space  between  the  slide  and  cover  glass.  By 
pulling  on  the  muscles  in  the  lower  part  of  the  limbs  it 
may  be  seen  that  those  on  the  back  side  bend  the  digits 
and  are  therefore  called  flexors,  while  those  on  the  front 
side  straighten  the  digits  and  are  accordingly  named  ex- 
tensors. Those  muscles  attached  to  the  upper  limb  regions 
pulling  them  outward  are  the  abductor -s,  while  those  draw- 
ing them  inward  like  the  great  breast  muscle  are  adductors. 


Brain 


Spleen* 
Stomach  \AovtaJena.Cava 


Des. 
Mon 


Esophagus1  rv  ^ 


Heart 


Liver 


\n       Jquntun, 
Duodenum 


FIG.  322.  —Diagram  of  the  chief  organs  of  a  mammal.  The  bones  are  black,  a, 
opening  from  the  nasal  cavity  s  to  pharynx  ;  bl,  bladder ;  ce,  caecum  ;  di,  dia- 
phragm ;  e,  epiglottis ;  n,  nostril  or  anterior  nares ;  ov,  ovary ;  rf  and  utet 
uterus  ;  ru  and  lu,  ureters ;  x,  pancreas ;  vag,  vagina.  From  Davison's  "  Mam- 
malian Anatomy." 

By  cutting  away  the  thin  layer  of  muscle  forming  the 
ventral  wall  of  the  body  cavity  the  internal  organs  may 
be  examined.  The  diaphragm,  a  thin  plate  of  muscle, 
divides  the  thoracic  cavity  containing  the  heart,  trachea, 
lungs,  and  esophagus  from  the  abdominal  cavity  contain- 
ing the  stomach,  intestines,  the  large  dark  red  liver  com- 
posed of  several  lobes  adjacent  to  the  diaphragm,  the 
pinkish-white  pancreas  lying  along  the  bend  of  the  intes- 


286 


VERTEBKATA 


tine  near  the  stomach,  the  dark-red  tongue-shaped  spleen, 
a  kidney  on  either  side  of  the  backbone,  and  a  pear-shaped 
urinary  bladder  into  which  two  ureters  lead  from  the 

kidneys.  The  thin 
transparent  mem- 
brane lining  the 
abdominal  cavity 
and  investing  the 
organs  therein  is 
the  peritoneum. 
The  similar  mem- 
brane in  the  thorax 
is  the  pleura.  These 
membranes  secrete 
a  colorless  serum 
and  are  therefore 
called  serous  mem- 
branes, to  distin- 
guish them  from 
the  •  mucous  mem- 
branes lining  the 
alimentary  canal 
and  all  other  cavi- 
ties to  which  the 
air  has  access. 

By  cutting  a 
small  slit  in  the 
windpipe  distinguished  by  its  numerous  incomplete  car- 
tilaginous rings,  and  inserting  and  tying  fast  therein  the 
end  of  a  small  glass  or  thin  tube  through  which  to  blow, 
the  lungs  may  be  inflated  as  in  inspiration  performed  by 


Fig.  323.  —  Photograph  of  a  lung  corrosion  prepared 
by  Mr.  Sylvester.  The  trachea  with  all  of  its 
branches  was  filled  with  melted  white  wax  and 
the  pulmonary  artery  was  filled  with  red  wax,  and 
the  specimen  then  placed  in  a  jar  of  acid  to  eat 
away  the  lung  tissue,  t,  trachea ;  a,  artery  to  right 
lung ;  6,  left  bronchus  giving  off  air  tubes  to  the 
left  lung.  The  expanded  air  sacs  at  the  ends  of  the 
minute  branchlets  are  broken  off.  FromDavison's 

i    "  Mammalian  Anatomy." 


MAMMALIA 


287 


the  living  animal.  The  two  vocal  cords  may  be  seen  by 
cutting  the  larynx  lengthwise.  They  are  flat  ligamentous 
folds  on  either  side 
of  the  larynx. 

The  vessels  re- 
maining full  of 
blood  are  the  veins. 
The  arteries  are  of 
a  lighter  color,  and 
contain  little  or  no 
blood.  The  main 
vein  of  the  trunk 
is  the  vena  cava, 
which  opens  into 
the  upper  right 
cavity  of  the  heart, 
called  the  right 
auricle.  From  here 
the  blood  passes 
to  the  right  lower 
cavity,  termed  the 
right  ventricle, 
which  by  the  con- 
traction of  its 
strong  muscular 
walls  forces  the 
blood  through  the 
pulmonary  artery 
to  the  lungs,  to  exchange  the  carbon  dioxide,  a  waste 
substance  collected  from  all  parts  of  the  body,  for 
oxygen.  The  blood  is  returned  from  the  lungs  bysev- 


FIG.  324.  —  Cat's  brain  viewed  from  above,  a,  &,  c, 
convolutions  of  the  cerebrum  ;  ce,  and  v,  cerebel- 
lum ;  md,  medulla  oblongata  ;  n,  stump  of  the 
nerve  supplying  the  shoulder  region  ;  sp,  spinal 
cord ;  ad,  body  of  nerve  cells  forming  the  gray 
matter  ;  ac,  processes  of  nerve  cells  forming  white 
matter.  Three  fourths  natural  size.  From  Davi- 
son's  "  Mammalian  Anatomy." 


cb 


•n, 


cc 


FIG.  325.  — Cat's  brain  viewed  from  beneath.  The  numbers  refer  to  the  nerves 
supplying  the  head  and  neck  ;  i,  io,  ir,  ex,  and  x,  muscles  for  moving  the  eye- 
ball ;  «,  optic  nerve  ;  op,  optic  chiasm  ;  ol,  olfactory  lobe ;  sy,  cerebrum  ;  cb, 
cerebellum ;  an,  medulla  oblongata ;  pv,  pons  Varolii ;  cc,  spinal  cord. 
Slightly  enlarged,  From  Davison's  "Mammalian  Anatomy."  (288) 


MAMMALIA 


289 


eral  veins  emptying  into  the  left  upper  cavity  known  as 
the  left  auricle  and  then  goes  to  the  left  ventricle,  which 
by  contraction  of  its  walls  propels  the  blood    through 
the  aorta   and  its 
branches     to     all 
parts  of  the  body. 
The      membranous 
valves,     held     by 
white  glistening 
cords,  between  the 
auricles   and   ven- 
tricles prevent  the 
backward   flow  of 
the  blood. 

The  nerves  are 
the  white  glisten- 
ing cords  extend- 
ing along  with  the 
blood  vessels  and 
giving  off  numer- 
ous branches  to  the 
muscles  and  other 
structures.  They 
are  connected 
either  with  the 
spinal  cord  or  the 
brain.  Those 
nerves  which  cariy  sense  stimuli,  such  as  sound  or  a  pin 
prick  to  the  brain  or  spinal  cord,  are  called  sensory  nerves, 
while  the  others  bearing  impressions  from  the  brain  or 
spinal  cord  to  the  muscles  are  termed  motor  nerves.  The 


FIG.  326.  —  Nerve  cell  from  the  brain  ;  a,  processes 
by  which  it  communicates  with  other  cells  near  by  ; 
ax,  long  process  or  axis  cylinder  terminating  in  the 
tail  end  of  the  spinal  cord  ;  n,  nucleus.  Enlarged 
two  Lundred  diameters.  From  Davison's  "  Mamma- 
lian Anatomy." 


290  VERTEBRATA 

spinal  cord  and  brain  form  the  central  nervous  system 
which  the  microscope  shows  to  be  composed  of  millions 
of  cells  with  processes  varying  in  length  from  a  hundredth 
of  an  inch  to  nearty  a  foot.  The  longer  processes  are 
called  fibers,  and  many  of  them  bound  together  form  a 
nerve  such  as  is  most  distinctly  seen  in  the  limbs. 

The  brain  of  mammals  is  composed  of  five  parts:  the 
medulla  oblongata,  the  cerebellum,  the  cerebrum  visible 
from  above,  and  the  rn'id  brain  and  interbrain  lying  beneath 
the  cerebrum.  The  intelligence  of  an  animal  seems  to 
depend  largely  on  the  size  and  structure  of  the  cerebrum. 
In  the  lower  mammals  the  surface  is  quite  smooth,  while 
in  the  rabbit  and  cat  it  is  somewhat  convoluted,  and  in  ape 
and  man  the  convolutions  become  very  numerous.  The 
average  weight  of  the  male  human  brain  is  about  three 
pounds;  of  a  female  about  two  and  two  thirds  pounds. 
The  human  brain  is  one  forty-fourth  the  weight  of  the  body ; 
the  ape's  one  twenty-ninth;  the  rat's  one  eighty-second; 
the  sheep's  one  three  hundred  and  fifty-first,  and  the  ele- 
phant's one  five-hundredth.  The  brain  of  man  is  larger 
than  that  of  any  other  animal  except  the  whale  and  ele- 
phant. The  brain  of  a  large  whale  weighs  over  four  pounds, 
while  that  of  a  large  elephant  will  weigh  about  ten  pounds. 

The  skeleton  of  the  cat  consists  of  more  than  two  hundred 
bones  united  to  each  other  by  tough  bands  of  tissue  called 
ligaments.  The  three  parts  of  the  skeleton  are  the  head, 
trunk,  and  extremities.  Except  the  lower  jaw,  the  bones 
of  the  head  are  immovably  united  to  each  other.  The 
bones  of  the  trunk  are  capable  of  only  limited  motion,  but 
free  movement  occurs  between  several  of  the  limb  bones. 
A  typical  mammalian  fore  limb  consists  of  a  shoulder  blade 


MAMMALIA 


291 


292  VERTEBRATA 

or  scapula,  the  arm  bone  or  humerus,  the  ulna  and  radius 
in  the  forearm,  several  small  bones  in  two  rows  forming 
the  carpus  or  wrist,  and  five  metacarpal  bones  in  the  hand, 
each  bearing  three  phalanges,  except  the  first,  which  has 
only  two.  In  the  hind  limb  the  femur  occupies  the  thigh 
region,  while  the  tibia  and  fibula  in  the  lower  part  of  the 
leg  join  the  several  small  bones  of  the  ankle  to  which  are 
united  the  five  bones  of  the  foot,  called  metatarsals,  each 
bearing  three  phalanges,  except  the  first,  which  has  only  two. 
In  many  forms  some  of  the  digits  are  wanting  and  others 
are  more  or  less  rudimentary,  as  in  the  cattle,  horses,  and 
pigs.  In  some  cases  the  ulna  and  radius  are  grown  to- 
gether, as  are  also  the  tibia  and  fibula,  and  in  these  species 
the  ulna  and  fibula  are  usually  rudimentary. 


PART  IV 
ANIMAL   LIFE 

20.    FROM   EGG  TO   ADULT 

Eggs  of  Animals.  —  With  the  exception  of  the  Protozoa, 
all  species  produce  specialized  cells  capable  under  certain 
conditions  of  developing  into  new  animals  similar  to  the 
parents.  Such  cells  are  known  as  ova  or  eggs.  These  are 
so  small  in  some  of  the  invertebrates  as  to  be  invisible  to 
the  naked  eye,  while  in  some  of  the  fish  the}'  are  as  large 
as  a  pinhead,  and  in  reptiles  and  birds  many  times  larger- 
The  egg  of  the  alligator  is  more  than  two  inches  in  diameter, 


FIG.  328.  —  Eggs  of  vert 
woodpecker 


tebrates,  a,  pond  turtle  ;  b,  black  snake  ;  c,  garter  snake  ;  rf, 
;  e,  lizard.    Photograph  two  thirds  natural  size. 


and  that  of  the  ostrich  is  more  than  six  inches.  The  real 
difference  between  the  small  egg  of  the  fish  and  the  large 
egg  of  the  bird  is  in  the  amount  of  the  yolk  and  albumen 


294  ANIMAL   LIFE 

stored  up  as  food  for  the  young.  Within  the  shell  of  a  hen's 
egg  is  sufficient  food  to  nourish  the  growing  chick,  called 
the  embryo,  until  it  is  able  to  run  about.  If  a  fresh  egg  be 
placed  in  water  and  a  circular  piece  of  shell  removed  with 
the  scissors,  a  white  spot  a  quarter  of  an  inch  in  diameter 
lying  on  the  yolk  is  seen.  This  is  a  young  chick  composed 


PIG.  329.  —  At  the  left  a  fresh  hen's  egg  showing  the  young  chick  at  the  center. 
At  the  right  an  English  sparrow  one  day  old.    Photograph. 

of  several  hundred  cells  which  have  developed  during 
twenty-four  hours  from  the  one  cell  formerly  occupying 
this  place.  Some  birds  are  in  a  helpless  condition  when 
hatched,  and  must  be  fed  by  the  parents  several  days  before 
they  can  fly  or  walk.  The  eggs  of  frogs  and  toads  contain- 
ing but  little  food  material  for  the  young  are  small,  and  in 
growing  the  whole  egg  may  be  seen  with  the  naked  eye 
to  divide  into  two  cells  within  two  or  three  hours  after 


FROM   EGG  TO   ADULT 


295 


FIG.   330.  — Strings  of  toads'  eggs  each  of  which  is  a  single  cell.    Photograph  nat- 
ural size. 


being  deposited  in  the  water.  An  hour  later  four  cells 
are  visible,  then  eight  cells,  after  which  division  occurs 
more  rapidly  (Fig.  332). 

Many  animals  retain  their  eggs  in  the  body  during 
development.  Such  are  certain  flesh  flies,  plant  lice, 
some  of  the  sharks,  the  copperhead,  rattlesnake,  and  most 
mammals. 

Development  of  Young.  —  In  numerous  species,  the 
young  does  not  continue  its  development  uninterruptedly 
but  at  certain  periods  rests  and  undergoes  remarkable 


296 


ANIMAL   LIFE 


FIG.  331.  —  Amphibian  egg  of  two 
cells  with  the  furrow  forming  to 
divide  it  into  four  cells.  Photo- 
graph through  the  microscope 
enlarging  twenty  diameters. 


changes  in  form  and  structure. 
The  egg  of  the  jellyfish  does 
not  produce  directly  the  free- 
swimming  parent  form,  but 
develops  into  what  is  known  as 
the  hydra  tube  (Fig.  203),  which 
after  a  time  by  transverse  di- 
vision gives  rise  to  several 
jellyfish.  The  egg  of  a  tape- 
worm eaten  by  an  animal 
becomes  in  a  favorable  host 
a  somewhat  globular  body 
known  as  the  cysticercus  or 
larva.  In  this  condition  it  may  live  for  months  or 
possibly  years  until  the  flesh  containing  it  is  eaten 
by  the  proper  host 
for  the  develop- 
ment into  the  com- 
plete tape  form.  The 
larva  of  the  cat's 
tapeworm  lives  in  the 
mouse,  and  the  tape- 
worm of  the  dog  is  a 
cysticercus  in  the  rab- 
bit (Figs.  184,  185). 

Among  the  insects 
very  marked  differ- 
ences in  form  occur 
during  the  life  of 

FIG.  332. — Frog's  eggs  from  three  to  ten  hours 

the  yOUng.       In   SOme  old.    All  stages  from  four  cells  to  thirty-two 

i  ,  ,-,  cells  may  be    noted.     Photograph   enlarged 

orders,   such  as   the        four  times. 


FROM  EGG  TO  ADULT 


297 


Neuroptera,  Coleoptera,  Diptera,  Lepidoptera,  and  Hymen- 
optera,  as  many  as  four  stages  are  distinguished  in  the  life 


FIG.  333.  —  One  fourth  of  the  eggs  laid  by  a  silk-worm  moth.    Twice  natural  size. 

cycle.    The  transformation  from  one  stage  to  the  next  is 
called  metamorphosis. 

The  egg  hatches  into  the  larva,  which  is  a  wingless  and 
often  wormlike  form  havino;  but  little  resemblance  to  the 


FIG.  334.  — Promethea  moth,  larva  and  adult.    Photograph  nearly  natural  size 


298  ANIMAL   LIFE 

parent.  The  larval  stage  may  continue  from 
three  days  to  three  years,  depending  largely 
on  the  species  but  somewhat  upon  the  food 
and  temperature.  It  is  longest  in  the  Coleop- 
tera  and  Neuroptera.  Before  entering  the 
third  stage,  that  of  pupat  the  larva  some- 
times forms  a  case  of  particles  of  earth,  or 
weaves  a  cocoon  from  its  silk  glands  or  from 
hairs  of  its  body  (Fig.  75).  The  deathlike 
sleep  of  the  pupa  continues  from  a  week  to  a 
year,  depending  upon  the  species.  No  food 
is  taken  and  any  temperature  from  twenty 
degrees  below  zero  to  one  hundred  degrees 
above  does  not  seem  to  harm  the  insect,  but 
the  wonderful  reorganization  of  structure 
necessary  to  assume  the  form  of  the  parent 
does  not  take  place  except  during  mild 
weather.  The  adult  stage  is  usually  a  winged 
form,  which  may  not  live  more  than  a  week, 
as  in  the  case  of  many  moths,  or  may  exist 
five  or  six  years,  as  in  the  case  of  the  queen 
honey  bee. 

Some  insects,  such  as  the  locusts,  grass- 
hoppers, cicadas,  dragon  flies,  and  May  flies, 
do  not  exhibit  any  marked  difference  in  form 
between  the  larval  and  pupal  states,  and  are 
therefore  spoken  of  as  having  an  incomplete 
metamorphosis  (Figs.  7,  140).  The  young  is 
then  usually  called  ihenymph 

FlG.  335.  —Metamorphosis  of  the  cicada  .  .  .  .. 

as  it  occurred   between  8  P.M.  and       and    Continues    active   at   all 

times.    Often  the  life  of  the 


FROM  EGG  TO   ADULT  299 

adult  insect  is  passed  in  a  realm  quite  different  from  that 
of  the  larva.  The  mature  dragon  flies,  May  flies,  and 
hellgramite  are  inhabitants  of  the  air,  while  the  larval 
young  dwell  in  the  water.  The  adult  cicadas  love  the 
pure  air  and  sunshine,  but  their  larvae  are  subterranean 
wanderers. 

Many  of  the  crustaceans  exhibit  a  complete  metamor- 
phosis, and  in  numerous  species  three  or  four  stages  are 
discernible.  In  the  case  of  the  small  crustaceans  (Ento- 
mostraca),  including  the  barnacles  and  shrimps,  the  larval 
form  hatching  from  the  egg  is  known  as  the  nauplius.  It 
differs  from  the  adult  in  having  usually  but  one  eye  and 
three  pairs  of  leglike  appendages  which  later  become  trans- 
formed into  the  antennules,  antennae,  and  mandibles. 
The  body  is  not  segmented.  In  the  barnacles  a  second 
larval  stage  occurs,  called  the  cypris,  characterized  by  a 
two-valved  shell,  six  pairs  of  swimming  feet,  and  paired 
compound  eyes.  Certain  of  the  larger  crustaceans  (Mala- 
costraca)  exhibit  two  stages  in  development  known  as 
zoea  and  my  sis.  The  larval  stages  last  but  a  few  days, 
and  in  any  species  are  passed  through  in  the  egg. 

Some  of  the  mollusks,  especially  the  bivalves,  pass 
through  a  larval  state  known  as  the  veliger.  It  is  a  minute, 
free-swimming  form.  In  the  case  of  the  fresh-water  mussel 
a  second  larval  stage  occurs,  while  as  a  parasite  it  is  at- 
tached to  a  fish.  The  eggs  of  the  sea-urchin  and  starfish 
do  not  hatch  directly  into  forms  resembling  the  parents, 
but  give  rise  to  young  differing  as  widely  from  the  adult 
as  the  caterpillar  differs  from  the  butterfly. 

Even  among  vertebrates,  as  in  the  case  of  some  fish  and 
all  amphibians,  the  development  from  egg  to  adult  is 


300 


ANIMAL  LIFE 


indirect.    The  larva  of  the  lamprey  eel  presents  features 
of  such  contrast  to  its  parent  that  for  many  years  it  was 


FIG.  336.  —  Metamorphosis  of  a  shrimp,     a,  nauplius  ;  b,  first  zosea  stage  ;  c,  sec- 
ond zosea  stage  ;  dt  mysis  stage ;  e,  adult.    From  Weismann  after  MUller. 

considered  an  animal  of  different  species  and  named  Ammo- 
coetes.  It  has  an  over-arching  upper  lip  instead  of  a 
round  sucking  mouth,  rudimentary  eyes,  and  gill  pouches 
opening  into  the  pharynx  instead  of  into  a  respiratory 


FROM   EGG   TO   ADULT 


301 


tube.    It  spends  four  or  five  years  in  the  mud  along  the 
banks  of  the  stream,  while  the  adult  is  a  free  swimmer 


2 


FIG.  337.  —  Life  cycle  of  the  frog  passed  through  in  four  months.    1,  mass  of  eggs; 
2,  month-old  legless  tadpole.    Photograph  one  half  life  size. 

(Fig.  215)  in  the  ocean.    The  young  of  the  bony  eel  is 
likewise  very  different  in  form  from  its  parent. 

Very  remarkable 
transformations  occur 
among  the  amphibians. 
Most  of  them  hi  the 
adult  state  are  air 
breathers,  but  with  few 
exceptions  the  larvse 


Fio   33S.  —  Axolotl  or  larval  form  of  an  am  bly- 
/toma.    Photograph  from  life. 


ANIMAL  LIFE 


are  aquatic.  The  common  toad,  though  a  lover  of  the 
dryest  soil,  habitually  repairs  to  the  quiet  pool  in  late 
spring  to  deposit  its  five  thousand  eggs  in  a  gelatinous 


FlG.  339. — Mature  Ainblystoma  one  half  natural  size. 

string,  from  whence  issue  in  a  week  the  well-known  black 
tadpoles,  legless  and  lungless,  and  in  fact  with  no  sem- 
blance to  their  warty 
mother.  They  breathe  by 
means  of  gills,  to  which 
there  is  a  small  opening 
on  the  left-hand  side  of  the 
neck.  In  a  month  or  two 
hind  legs  appear  and  the 
front  ones  break  through 
the  skin  as  the  tail  begins 
to  be  absorbed.  Mean- 
while, lungs  have  developed 
witliin  and  the  young,  an 
inch  or  less  in  length,  are 

ready     for      life     On     land.       FIG.  340.  —  Embryo  snake  within  the  egg 
<«_  f  ,-,  , .  from  which  the  top  of  the  shell  has 

Progs  frequently  continue       been  cut  away. 


SENSES   OF   ANIMALS  303 

in  the  larval  stage  over  winter,  hiding  in  the  mud  at  the 
bottom  of  the  ponds.  One  of  the  urodeles,  the  axolotl, 
usually  continues  in  its  larval  condition  throughout  life. 
The  drying  up  of  the  water  causes  it  to  assume  the  adult 
form  when  it  is  known  as  an  amblystoma.  Cold  and  lack 
of  food  may  prolong  the  larval  life  of  some  species  several 
months. 

Among  the  higher  vertebrates  the  developing  young,  up 
to  the  time  when  it  assumes  the  characteristic  form  of 
the  parent,  is  called  the  embryo. 

21.     SENSES   OF    ANIMALS. 

Sense  of  Feeling.  — There  are  probably  no  animals, 
however  simple  in  structure,  which  do  not  respond  to  cer- 
tain kinds  of  stimuli.  While  it  is  true  that  none  of  the 
protozoa  or  sponges  and  but  few  of  the  worms  and  mol- 
lusks  can  see  or  hear,  yet  the  sense  of  feeling  seems  to  be 
present  in  all  animal  life.  The  amoeba  can  distinguish 
between  a  particle  of  sand  and  a  bit  of  flesh.  The  Para- 
mceeium  brought  from  darkness  into  bright  light  responds 
by  vigorous  movements,  owing  doubtless  to  the  fact  that 
the  protoplasm  of  all  parts  of  the  body  is  sensitive  to  the 
light  rays,  but  the  animal  can  not  be  said  to  see.  The 
more  complex  the  nervous  system  the  more  acute  is  the 
sense  of  feeling,  which  is  the  only  sense  with  organs 
widely  distributed  over  the  body.  The  most  sensitive 
parts  in  the  Hydra  and  sea  anemone  (Fig.  342)  are  the 
tentacles.  The  loss  of  a  leg  or  wing  or  even  of  a  portion 
of  the  body  of  an  insect  seems  to  cause  the  creature  little 
or  no  pain.  With  a  pair  of  sharp  scissors  one  may 
cut  a  third  of  the  abdomen  off  the  mosquito  while  it  is 


304 


ANIMAL   LIFE 


sucking  blood,  and  the  parasite  will  in  some  cases  continue 
feeding. 

Among  the  higher  vertebrates  some  areas  of  the  skin  are 
more  sensitive  than  others.  If  the  points  of  two  phis  be 
pressed  to  the  skin  at  a  distance  of  less  than  two  inches 


PIG.  341.  —The  slipper  animalcules  (Paramceciuni).    Photograph  from  life  through 
the  microscope. 

apart  on  the  middle  of  the  human  back,  only  one  point 
will  be  felt,  but  on  the  tip  of  the  tongue  two  separate 
points  may  be  distinguished  when  only  one  twenty-fifth 
of  an  inch  apart.  In  the  higher  animals  the  sense  of  feel- 
ing depends  upon  the  presence  of  special  nerve  termina- 
tions from  which  lead  nerve  fibers  to  the  spinal  cord  or 


SENSES   OF   ANIMALS  305 

brain.  In  the  mesentery  of  the  cat  the  oval  nerve  ter- 
minations are  just  large  enough  to  be  clearly  visible  to  the 
naked  eye  (Fig.  343). 

The  sense  of  taste  is  located  in  the  mouth  or  near  the 
entrance  to  it.     Among  mammals  it  depends  upon  certain 


FIG.  342.  —  Sea  anemone,    m,  mouth ;  the  projecting  mass  at  the  right  is  a  bud 
which  will  soon  form  a  new  animal.    Photograph  two  thirds  natural  size. 

nerve  terminations  in  the  mucous  membrane  of  the  tongue, 
palate,  and  neighboring  regions.  Special  flask-shaped 
endings  are  numerous  in  the  several  large  papilla  arranged 
in  a  V-shape  at  the  back  of  the  tongue.  So  acute  is  the 
sense  of  taste  in  the  human  that  a  woman  is  said  to  have 
detected  one  part  of  quinine  in  five  million  parts  of  water. 
Little  is  known  concerning  the  sense  of  taste  in  the 


306 


ANIMAL  LIFE 


FIG.  343.  —  Sensory  nerve  ter- 
mination in  the  mesentery  of 
the  cat.  From  Davison's 
"  Mammalian  Anatomy." 


lower  vertebrates,  but  numerous 
experiments  have  been  made  with 
insects.  Most  caterpillars  will  re- 
fuse all  but  one  or  two  kinds  of 
leaves,  and  many  bugs  will  die  of 
starvation  rather  than  suck  the 
juice  of  plants  to  which  they  are 
not  accustomed.  When  the  sugar 
upon  which  bees  are  feeding  is  ex- 
changed for  pulverized  alum,  the 
insects  splutter  and  spit  in  a  way 
that  indicates  a  well-developed 
sense  of  taste.  Ants  love  sugar, 
but  if  strychnine  is  mixed  with  it 

they  reject   the   food   at   once.    The  organs  of  taste  in 

insects  are  minute  pits  containing  fine 

taste  hairs.    They  are  present  in  the 

maxilla  and  tongue  of  ants,  bees,  and 

wasps,  and  on  the  proboscis  of  the 

flies. 
The  sense  of  smell  varies  widely  in 

efficiency  among  the  different  animals. 

It  is  well  developed  in  most  terrestrial 

mammals,  but  more  or  less  rudimen- 
tary in  the  other  classes  of  vertebrates. 

A  dog   familiar    with    the    smell    of 

his  master  can  track  him  through  a 

crowded   street   with   the   same    ease 

that  we  can  follow  a  man  by  sight.    A 

deer  will  discern  the  presence  of  man 

a  half  mile  distant  to  windward.    It 


FIG.  344.  — Head  of  the 
bumblebee,  a,  anten- 
na ;  g,  glossa  or  tongue 
used  in  licking  the  nec- 
tar from  flowers ;  lt 
paraglossa;  m,  maxil- 
lae. Photograph. 


SENSES   OF  ANIMALS  307 

is  probaHe  that  a  few  birds  and  also  fish  use  the  sense 
of  smell  in  seeking  food.  The  special  end  organs  of  this 
sense  in  the  vertebrates  is  located  in  the  mucous  membrane 
lining  the  upper  parts  of  the  nasal  cavity,  whence  a  pair 
of  nerves  convey  the  stimuli  to  the  brain. 

With  the  exception  of  arthropods,  but  little  is  known 
concerning  the  sense  of  smell  among  the  invertebrates. 
Many  insects  have  a  keen  sense  of  smell.  A  piece  of  decay- 
ing meat  so  covered  that  it  can  not  be  seen  will,  on  a  warm 
day,  attract  numerous  flies,  some  of  which  apparently  scent 
it  at  a,  distance  where  no  odor  is  discernible  to  man.  Many 
of  the  social  insects  recognize  the  members  of  their  house- 
hold by  smell,  and  the  male  of  some  species  seeks  his  mate 
by  the  olfactory  sense.  Among  insects  the  organs  of  smell 
are  located  in  the  antennae  or  palps.  Male  bumblebees 
with  the  antennae  removed  can  not  find  their  mates  (Fig. 
344).  Some  crustaceans  seem  to  possess  organs  of  smell 
on  the  antennules. 

The  sense  of  hearing  is  most  acute  in  mammals  and  birds. 
The  organ  of  hearing,  which  is  a  portion  of  the  internal 
ear  located  on  either  side  of  the  head,  responds  to  certain 
vibrations  productive  of  sound  waves  in  the  atmosphere. 
It  is  probable  that  all  normal  vertebrates  with  the  excep- 
tion of  some  fish  and  certain  tailed  amphibians  are  capable 
of  hearing.  In  the  frog,  the  large  round  tympanic  mem- 
brane back  of  the  eye  (Fig.  239)  is  similar  to  the  tympanic 
membrane  of  birds  and  mammals  located  at  the  inner  end 
of  a  short  canal  on  either  side  of  the  head.  It  transmits 
the  vibrations  affecting  it  to  the  inner  ear,  which  is  an 
irregular  sac  filled  with  liquid,  and  containing  the  termina- 
tions of  the  nerve  of  hearing.  No  tympanic  membrane 


808  ANIMAL  LIFE 

is  present  in  fish,  salamanders,  or  snakes,  which  fact  ac- 
counts in  part  for  their  partial  deafness. 

More  simple  auditory  organs  are  found  among  some  of 
the  invertebrates.  These  consist  of  small  sacs  containing 
a  clear  liquid  with  one  or  more  tiny  lime  nodules,  called 
otoliths.  Specialized  cells  often  bearing  vibratile  hairs 
line  more  or  less  of  the  inner  surface  of  the  sac.  Organs 
of  hearing  or  equilibration  are  present  in  the  margin  of  the 
umbrella  of  certain  jellyfish,  in  the  head  of  a  few  worms, 
in  the  foot  of  the  mussel,  in  the  head  of  the  snail,  in  the 
first  segment  of  the  antennules  of  the  crayfish,  and  in  some 
other  crustaceans  in  the  tail.  Hearing  among  insects  is  in 
many  species  quite  acute,  and  it  is  probable  that  they  are 
aware  of  some  sounds  that  make  no  impression  on  our 
ears.  In  a  few  insects  a  vibrating  tympanic  membrane 
occurs  as  may  be  seen  in  the  common  locust,  having  the 
ear  on  the  side  of  the  first  abdominal  segment.  The  true 
grasshoppers  and  crickets  have  an  ear  on  the  front  leg.  The 
oval  tympanic  membrane  may  be  seen  with  the  naked  eye 
on  the  outer  surface  of  the  tibia  of  the  common  large 
cricket.  It  has  the  same  location  in  ants.  Certain  other 
insects  possess  a  complex  organ  of  hearing  at  the  base  of 
each  antenna. 

Sight  is  undoubtedly  the  most  important  sense  of  all  for 
animals  living  in  the  light,  because  it  not  only  aids  them 
greatly  in  securing  food,  but  also  in  escaping  from  their 
enemies.  All  vertebrates  have  eyes  or  rudiments  of  them. 
Moles  living  underground,  insects,  crustaceans,  fish,  and 
amphibians  inhabiting  caves,  and  some  fish  living  at  great 
depth  in  the  sea  have  eyes  of  such  a  rudimentary  char- 
acter as  to  be  of  no  use.  The  larger  mammals  can  sight 


SENSES  OF  ANIMALS 


309 


objects  at  a  distance  of  many  miles,  but  the  keenest  vision 
is  probably  possessed  by  birds.  A  fish  hawk  at  a  distance 
of  two  hundred  feet  will  spy  a  fish  in  the  stream  when 
human  vision  can  not  detect  it  fifty  feet  away.  The 
chimney  swift, 
wheeling  through 
the  summer  air,  no 
doubt,  sees  the 
minute  insects  con- 
stituting its  food. 
Most  of  the  lower 
vertebrates  are 
decidedly  short- 
sighted. A  toad 
does  not  recognize 
a  fly  at  a  distance 
of  more  than  two 
or  three  feet,  and 
few  common  fish 
distinguish  food 
beyond  five  feet. 

The  structure  of  the  vertebrate  eye  is  admirably  adapted 
for  its  function.  The  eyeball  is  composed  of  the  tough, 
thick  sclerotic  coat,  the  thin  black  choroid  coat,  and  the 
pinkish  retina  almost  surrounding  the  vitreous  humor  which 
is  separated  from  the  aqueous  humor  by  the  crystalline 
lens  adjustable  for  far  and  near  vision.  The  parts  of  an 
eye  of  a  cat,  cow,  or  fish  may  be  easily  seen  by  cutting  it 
in  two  with  a  sharp  knife.  The  structure  is  especially  well 
shown  in  an  eye  frozen  before  being  cut. 

Many  of  the  cdeleriterates,  echinoderms,   worms,  and 


rt 


FIG.  345.  —  Section  of  the  cat's  eye  enlarged  twice. 
aq,  aqueous  humor  ;  c,  cornea ;  ci,  ciliary  pro- 
cesses ;  cp,  capsule  surrounding  the  crystalline 
lens  ;  ch,  choroid  coat ;  i,  iris  ;  lg,  ligament  of  the 
lens  ;  m,  muscle  to  adjust  the  lens  for  far  and  near 
sight ;  opn,  optic  nerve  leading  to  the  brain ;  rt, 
retina ;  sc,  sclerotic  coat.  From  Davison's 
"  Mammalian  Anatomy." 


310  ANIMAL  LIFE 

mollusks  have  no  eyes,  but  they  are  usually  sensitive  to  light. 
The  simplest  eyes  are  found  in  the  jellyfish,  and  organs  of 
sight  somewhat  resembling  those  of  the  vertebrates  are 
present  in  the  scallop  (Pecten)  and  cephalopods  (squid,  cut- 
tlefish, etc.).  The  snail  has  well-developed  eyes  on  stalks. 
The  insects  and  crustaceans  have  acute  vision,  but  at 
a  distance  of  only  a  few  feet.  Both  compound  and  simple 
eyes  are  present  in  most  insects.  If  the  compound  eye  of 
a  house  fly  be  placed  under  the  low 
power  of  the  microscope  the  surface 
will  appear  marked  off  in  hexagonal 
areas.  These  are  the  ends  of  cones, 
each  of  which  may  function  as  a  sepa- 
rate eye.  The  queen  bee  has  five  thou- 
sand of  them,  the  drone  twelve  thou- 
sand>  the  draS°n  fly  twenty  thousand, 


tenna  ;    e,  compound    and  SOme  beetles  twenty-five  thousand. 

eye;   the  three   black  . 

dots  are  the  simple  Ihe  simple  eyes,  called  ocelli,  located 
near  the  middle  of  the  forehead,  are 
just  visible  to  the  naked  eye  in  such  large  forms  as  the 
locust  in  which  there  are  three.  These  are  probably  used 
for  very  near  vision.  Spiders  have  no  compound  eyes, 
but  from  six  to  eight  ocelli  larger  than  those  of  insects. 

22.  PROTECTION  FROM  ENEMIES 

Every  living  animal  from  the  amoeba  to  man  has  enemies 
seeking  its  destruction,  and  it  is  only  by  special  adapta- 
tions that  the  species  persists.  The  huge  elephantlike 
Titanotheres  and  Uintatheres  which  a  few  millions  of 
years  ago  roamed  about  in  Western  United  States,  became 


PROTECTION   FROM  ENEMIES  811 

extinct  because  they  had  no  means  of  protecting  them- 
selves from  the  furious  saber-toothed  tigers  and  other  blood- 
thirsty carnivores  of  those  days.  The  buffalo  of  the  west- 
ern plains,  the  fur  seal  of  Alaska,  and  the  trout  of  the 
mountain  stream  are  being  overcome  in  the  struggle  for 


FIG.  347.  —  Larva  of  caddis  fly.    Natural  size. 

existence,  because  they  have  no  means  of  adequately  pro- 
tecting themselves  from  their  arch  enemy,  man. 

Many  animals  are  provided  with  an  external  armor 
preventing  the  attack  of  would-be  foes.  The  sea  urchins 
are  covered  with  spines,  many  of  the  mollusks  are  inclosed 


FIG.  348.— Photograph  of  io,  a  poisonous  caterpillar. 

in  calcareous  shells,  some  of  the  marine  worms  live  in  hard- 
walled  tubes,  and  the  larvae  of  some  insects  such  as  the 
caddis  flies  dwell  in  protecting  tubes,  while  many  cater- 
pillars are  covered  with  stiff  or  poisonous  hairs.  The  hard 
shell  of  the  crustaceans  and  the  adopted  home  of  the  hermit 


312 


ANIMAL  LIFE 


crab  are  effective  means  in  reducing  the  mortality  among 
these  forms.  The  hard  shell  of  the  chelonians,  the  thick 
skins  of  the  alligator,  tapir,  and  hippopotamus,  the  series 
of  bony  plates  covering  the  armadillo,  and  the  spines  of 
the  hedgehog,  form  armors  of  great  value  in  the  midst 
of  hostile  associates. 

Special  weapons  of  defense  have  been  developed  among 
some  groups,  as  in  the  case  of  the  wasps  and  bees  which 
prevent  the  robbing  of  their  homes  and  the  killing  of  the 
young,  by  the  use  of  poisonous  stings.  Men  have  been 
known  to  die  as  the  result  of  an  attack  by  a  colony  of  bees. 
The  tarantula  and  tropical  centipeds  protect  themselves 


FIG.  349.  —  The  rattlesnake  defending  itself  against  an  enemy,  f,  poison  fang;  h, 
hood  holding  the  tooth  against  the  roof  of  the  mouth  when  not  in  action. 
Photograph  of  posed  dead  snake.  One  third  life  size. 

by  attacking  the  enemy  with  their  poisoned  mandibles, 
while  the  scorpion  releases  itself  from  its  tormentor  by 
applying  its  poisonous  fang  at  the  end  of  the  tail.  The 
torpedo,  a  flat-bodied  fish  of  the  Atlantic  coast,  and  the 
six-foot  electric  eel  of  the  South  American  waters  give  a 


PROTECTION   FROM  ENEMIES  318 

severe  electric  shock  to  any  foe  daring  to  touch  them. 
Some  of  the  catfish  possess  poisoned  barbs  in  the  thoracic 
fin  which  are  used  in  contests.  A  few  of  the  snakes  have 
a  pair  of  long  teeth,  called  fangs,  in  the  upper  jaw,  through 
which  they  inject  into  any  creature  disturbing  them  a 
deadly  poison.  The  rattlesnakes,  copperhead,  and  south- 
ern moccasin  are  the  only  poisonous  snakes  to  be  feared 
in  our  country. 

Among  mammals  the  weapons  of  defense  are  varied. 
The  antlers  of  the  deer  and  the  horns  of  the  cattle  are  often 
used  with  telling  effect  against  their  foes.  The  tusks  of 


FIG.  350.  —  Kallima  butterfly  on  the  right,  leaf  on  left.    Photograph  life  size- 


314 


ANIMAL  LIFE 


the  elephant  render  him  a  formidable  opponent.  The 
long  sharp  incisors  of  the  rodents  and  the  pointed  teeth  of 
the  bats  afford  them  sufficient  aid  in  contests  with  larger 
animals.  The  large  canines  of  the  carnivora  and  the  strong 

sharp  claws  of  the 
lion  and  tiger  are 
weapons  of  great 
power.  Some  of  the 
carnivores,  espe- 
cially the  skunks, 
protect  themselves 
by  the  ejection  of  a 
nauseous-  smelling 
fluid  detested  by 
dogs,  foxes,  and 
wolves. 

Many  animals 
without  a  protective 
armor  or  special 
weapons  of  defense 
seek  safety  in  flight. 
Such  are  the  hares, 
kangaroos,  and  some 
birds.  Others  es- 
cape by  assuming 
such  attitudes  and 
colors  as  to  make  it 
difficult  for  their  enemies  to  distinguish  them  from  the  sur- 
rounding objects.  The  leaf  butterfly  (Kallima)  of  India 
when  at  rest  on  certain  bushes  is  so  similar  to  the  leaves 
that  even  the  birds  fail  to  distinguish  the  difference.  The 


FIG.  351.  — The  walking  stick  (Diapheromerafem- 
orato).     Natural  size. 


PROTECTION  FROM  ENEMIES 


315 


katydids,  so  numerous  in  late  summer,  have  a  green  color 
and  venation  of  the  wings,  making  them  so  inconspicuous 
among  the  green  leaves  that  the  birds  seldom  detect  them 
unless  they  move.  The  walking  stick  insects  resemble  so 
closely  the  twigs  of  the  trees  among  which  they  live  that 
only  the  acutest  vision  spies  the  creatures  so  long  as  they  re- 
main motionless.  I  have  known  as  many  as  twenty  locusts 
to  sit  in  the  grass  within  the  range  of  distinct  human  vision 
and  yet  be  invisible  until  they  were  disturbed.  Such 
protective  resemblance  prevents  the  birds  and  other  ene- 
mies from  exterminating  the  species. 

The  measuring  worms,  larva?  of  geometrid  moths,  imi- 
tate so  closely  the 
short  rough  twigs 
that  I  have  had  to 
touch  the  suspi- 
cious object  with 
my  hand  before  I 
could  be  quite  sure 
that  it  was  really 
an  animal.  Many 
of  the  green  larvae 
feeding  on  green 
foliage  escape  the 
eyes  of  their  pur- 
suers because  of 
their  protective 
colors.  Some  of 
the  crabs  take  on  the  somber  color  of  the  rocks  and 
stones  among  which  they  dwell,  and  sometimes  bear  on 
their  shells  growths  of  seaweed  and  hydroids.  Spiders 


FlG.  352.  —  The  projection  on  the  right  is  a  geometrid 
larva.    Photograph  life  size. 


ANIMAL  LIFE 


FIG.  353.  —  Spider  crab  often  found  covered  with  seaweeds  and  hydroids  so  as  to 
appear  like  a  stone  or  stick.    Photograph  by  Overton.    One  third  natural  size. 


FlG.  354.  —  Tree  frog.    A,  after  assuming  a  protective  color ;  B,  before  assuming 
the  dark  protective  color  of  the  bark  which  it  took  on  fifteen  minutes  later. 


Photograph  nearly  half  life  size. 


PROTECTION  FROM  ENEMIES          317 

in  Java  resemble  so  closely  bird  droppings  that  a  trained 
eye  can  not  detect  the  difference  unless  at  close  range. 

The  markings  of  many  fish  are  such  as  to  harmonize 
so  completely  with  the  variously  colored  bed  of  the  stream 
that  the  casual  observer  will  not  see  them  when  only  a  few 
feet  distant  in  clear  water.  The  tree  frog  is  a  notable 
example  of  the  ability  of  an  animal  to  adapt  its  color  to  its 
environment.  It  is  able  to  change  its  color  from  a  very 
dark  hue  to  a  very  light  one  in  about  twenty  minutes,  and 
so  perfectly  does  it  agree  in  color  with  the  surface  of  a  stone, 
a  lichen,  or  the  bark  of  a  tree  that  often  one  is  not  aware 
of  its  presence  until  he  has  accidentally  placed  his  hand 
on  it.  The  common  frogs  are  likewise  protected  by  the 
ability  to  change  the  color  of  the  skin.  Certain  lizards 
and  snakes  render  themselves  very  inconspicuous  by 
taking  advantage  of  protective  coloration. 

A  woodcock  on  her  nest  has  been  known  to  have  so 
much  faith  in  the  protection  afforded  her  by  the  brown- 


G.  355.  — Adult  woodcock  and  twoyotmg  rendered  inconspicuous  by  their  envi- 
ronment.   Photographed  in  American  Museum. 


318 


ANIMAL  LIFE 


FIG.  356.  —  The  whip-poor-will  showing  protective  coloration.    Photographed  in  the 
Academy  of  Natural  Sciences,  Philadelphia.    One  third  life  size. 


FIG.  357.— Protective  resemblance  in  the  bobwhite.    Photographed  in  the  Acad- 
emy of  Natural  Sciences. 


PROTECTION   FROM  ENEMIES 


319 


leaf  plumage  of  April  that  she  would  permit  a  person  to 
approach  within  a  foot  or  two  of  her  nest.  A  light  snow- 
fall occurring  a  few  days  later  made  the  same  bird  con- 


FIG.  358. — The  ptarmigan  in  summer.    Photograph  of  mounted  specimen.     One 
third  life  size. 

spicuous,  and  she  would  fly  from  her  nest  before  the  ob- 
server was  nearer  than  fifty  feet.  The  whip-poor-will  as  it 
sits  among  the  dead  leaves  in  the  depth  of  the  forest  appears 
not  unlike  a  mass  of  leaves  some  of  which  are  browner 
than  others.  The  hunter,  standing  within  ten  feet  of  a 


320  ANIMAL  LIFE 

large  flock  of  quail,  can  not  see  a  bird  until  it  flies,  because 
the  dull-colored  plumage  so  effectually  resembles  the 
autumn  leaves  and  tangled  grass.  The  little  screech  owl 
with  his  gray  and  brown  feathers  becomes  inconspicuous 
against  the  somber-hued  barks  of  the  forest.  The  ptar- 
migan adjusts  its  plumage  in  accordance  with  the  season, 


FIG.  359  —  The  ptarmigan  in  winter.    Photograph  of  mounted  specimen. 

being  brown  in  summer  and  white  in  winter.  The  arctic 
fox  and  hare  exhibit  the  same  seasonal  change.  Most 
animals  of  the  arctic  regions  are  white,  as  that  is  the  most 
protective  color  for  the  land  of  snow.  The  weasel  in  the 
northern  part  of  the  United  States  and  Canada  is  brown 
in  color  during  the  warm  months,  but  becomes  after  snow- 
fall in  early  winter  a  pure  white,  except  the  tip  of  its  tail. 

Some  animals  are  protected  by  their  likeness  to  the  form 
of  others  which  for  various  reasons  are  left  unharmed. 


PROTECTION  FROM  ENEMIES          321 

This  phase  of  protective  coloration  is  known  as  mimicry. 
Certain  flies  resemble  the  stinging  bees  so  closely  that  one 
must  catch  them  before  he  can  be  quite  sure  of  their 
identity.  Some  butterflies  have  wings  like  those  of  a 
few  species  which  are  left  untouched  by  the  birds  because 


PIG.  360. — The  snowy  owl  visiting  the  United  States  only  in  winter.     Photo- 
graph of  specimen  mounted  by  Neal.    One  sixth  life  size. 

of  their  bad  flavor.  The  spotted  adder  (Fig.  248),  a  com- 
mon harmless  snake,  when  disturbed  by  an  enemy  coils 
and  vibrates  the  end  of  its  tail  much  after  the  fashion 
of  the  rattlesnake. 

Were  it  not  for  protective  coloration  and  mimicry  among 
animals  certain  species  would  doubtless  have  suffered  ex- 


322 


ANIMAL  LIFE 


FIG.  361.  —  The  weasel  in  summer  with  its  prey,  the  mouse.     Photographed  in  the 
American  Museum  of  Natural  History.     One  sixth  natural  size. 


tinction.  It  must  be  understood  that  these  character- 
istics are  secured  to  the  species,  not  by  its  own  will  power, 
but  through  a,  process  of  variation  and  natural  selection. 


FIG.  362.— The  weasel  in  winter.     Photographed  in  the  American  Museum  of 
Natural  History. 


PARASITISM  323 

During  many  years  in  the  past  those  which  did  not  possess 
protective  features  were  killed  by  the  ever-pursuing  ene- 
mies, while  the  survivors  transmitted  to  their  offspring 
their  special  protective  characteristics. 

23.   PARASITISM 

Symbiosis.  — •  There  are  certain  species  of  animals  which 
are  always  found  in  association  with  certain  other  species, 
because  in  the  struggle  for  existence  they  are  mutually 
helpful.  The  ants  are  often  to  be  seen  in  company  with 
the  plant  lice  which  feed  on  the  sap  in  the  tender  twigs  and 
leaves.  From  the  alimentary  canal  of  the  plant  lice  exudes 
a  sweet  fluid  much  sought  after  by  the  ants.  The  ants 
assist  the  lice  by  transporting  them  to  the  tenderest  parts 
of  the  plant,  and  in  some  cases  during  inclement  weather 
even  remove  them  to  places  of  shelter.  This  condition 
of  intimate  association  for  mutual  benefit  is  known  as 
symbiosis.  Some  of  the  crabs  bear  on  their  back  sponges 
which  render  them  less  easily  visible  to  their  enemies,  and 
the  crab  repays  the  kindness  by  carrying  the  sponges  to 
good  feeding-grounds. 

True  Parasites.  —  A  still  closer  association  between 
species,  where  only  one  derives  any  benefit,  represents  a 
condition  designated  parasitism.  The  animal  which  thrives 
by  feeding  on  the  living  blood  or  tissue  of  another  called 
the  host  is  a  parasite.  Parasitic  animals  are  found  among 
nearly  all  the  subkingdoms,  but  they  are  the  most  numer- 
ous among  the  protozoans,  worms,  and  arthropods.  Only 
about  a  dozen  species  of  vertebrate  parasites  are  known. 
They  are  the  lamprey  eels  (Fig.  215)  and  hagfish,  which 


324 


ANIMAL   LIFE 


FIG.  363.  —  Photograph  from  life  of  the  mouth  of 
the  lamprey  eel  sucked  fast  to  a  piece  of  glass. 
Natural  size. 


become  the  guests  of 
other  fish  whose  blood 
and  mucus  they  suck 
by  attaching  to  their 
sides. 

Parasitic  Protozoa. 
—  Among  the  Proto- 
zoa, the  commonest 
parasites  are  the 
Amoeba  dysenterica,  in- 
habiting the  intestine 
of  man  and  causing 
one  kind  of  dysentery; 
the  Plasmodium  malarice,  residing  in  the  human  blood 
corpuscles  and  producing  malarial  fevers;  the  Opalina, 
of  which  hundreds 
are  present  in  the 
large  intestine  of 
the  frog,  and  the 
Gregarina,  abun- 
dant in  the  alimen- 
tary canal  of  the 
earthworm,  lob- 
ster, and  many 
beetles. 

Parasitic  Worms. 
—  Of  parasitic 
worms  there  are 
more  than  a  hun- 
dred species,  most 
of  which  live  at  the 


FIG.  364.  —  The  malarial  parasite  photographed 
through  a  microscope  magnifying  one  thousand 
diameters.  Two  individuals  are  present  in  the 
red  blood  corpuscles. 


PARASITISM 


825 


expense  of  the  vertebrates.  The  most  dreaded  of  the  round 
worms  is  the  Trichina  living  in  the  flesh  of  hogs,  rats,  dogs, 
and  man.  One  animal  becomes  infected  by  eating  the  flesh 
of  another  containing  the  parasites  which  upon  reaching 
the  stomach  of  the  new  host  bring  forth  many 
young  ones.  These  migrate  through  the 
walls  of  the  alimentary  canal  into  the  mus^ 
cles  and  remain  there  in  a  living  condition 
many  months,  never  again  becoming  active 
until  eaten  by  a  new  host.  The  government 
meat  inspectors  have  found  as  many  as 
seventeen  thousand  hogs  containing  this  par- 
asite in  one  year.  A  microscopic  worm, 
Filaria,  occurring  in  the  blood  of  man  in  the 
tropical  regions,  produces  various  disorders. 
Among  the  larger  parasites  is  the  stomach 
worm,  Ascaris  lumbricoides,  from  three  to  six 
inches  long,  affecting  children,  and  various 
other  species  of  Ascaris  are  common  in  nearly 
all  mammals.  They  hold  on  to  the  mucous 
coat  of  the  stomach  or  intestine  by  means 
of  a  hook  at  the  hind  end,  and  feed  on  the 
digested  food.  Eggs  are  produced  at  the  rate 
of  about  fifteen  thousand  daily,  and  passing 
out  with  the  excrement  may  reach  the  water 
supply  and  infect  new  individuals.  Strongylus  is  a  genus 
containing  many  species  of  minute,  round  worms  parasitic 
in  the  mammals,  birds,  and  frogs.  Some  kinds  occupy 
the  digestive  system  while  others  are  present  only  in  the 
respiratory  organs.  Nine  out  of  every  ten  cats  harbor 
round  worms  of  some  kind. 


FIG.  365.  —  Tri- 
china. 1,  fe- 
male ;  2,  male. 
Enlarged  fifty 
times. 


826 


ANIMAL  LIFE 


The  flat  worms  are  parasitic  in  all  classes  of  vertebrates. 
The  liver  fluke,  annually  causing  the  death  of  thousands 
of  sheep  in  Great  Britain  and  South  America,  inhabits  the 
bile  ducts  in  its  adult  stage,  while  during  its  early  develop- 
ment it  swims  free  in  the  water  and  later  becomes  para- 
sitic in  the  pond  snail.  After  a  time  it  escapes  from  the 
snail  and  becomes  encysted  on  a  grass  blade,  where  it  re- 
mains until  eaten  by  the  sheep. 

The  tapeworms,  various  species  of  which  inhabit  the  ver- 
tebrates from  fish  to  man,  attain  the  largest  size  of  any  of 

the  parasites,  speci- 
mens having  been 
reported  over  fifty 
feet  in  length.  They 
are  characterized  by 
a  small  head  (scolex) 
bearing  hooks  or 
suckers  for  anchor- 
age in  the  wall  of 
the  alimentary  tract, 
a  tapelike  body  com- 
posed of  numerous 
segments,  called 
proglottides,  and 
the  absence  of  a 
digestive  canal.  They  are  nourished  by  the  absorption 
through  their  body  walls  of  the  digested  liquid  food  of 
the  smaller  intestine.  The  eggs,  which  the  worms  mature 
by  the  thousands  daily,  can  not  develop  within  the  host, 
but  pass  out,  and  upon  being  taken  in  with  food  or  drink 
by  certain  animals  hatch  into  spherical  forms  with  six 


FIG.  366.  —  A  tapeworm  from  the  cat.   h,  head; 
pt  posterior  end.    Nearly  life  size. 


PARASITISM 


327 


hooks.  Very  soon  each  one  migrates  from  the  alimentary 
canal  to  the  muscles,  liver,  or  peritoneum,  and  forms  about 
itself  a  sac  or  cyst,  and  is  then  known  as  a  cysticercus. 
Before  any  further  growth  can  occur  it  must  reach  the 
alimentary  canal  of  the  same  species  as  that  in  which 
its  parent  lived.  Tcenia  solium,  a  tapeworm  occasionally 
present  in  man,  passes  its  larval  stage  in  the  flesh  of  the 
pig,  while  the  cysticercus  of  the  other  human  tapeworm 
is  found  in  beef.  In 
some  regions  one  out 
of  every  five  rabbits 
contains  the  cysticerci 
of  the  dog's  tapeworm 
in  the  liver  or  perito- 
neum. They  are  oval 
white  bodies  from  a 
fourth  of  an  inch  to 
half  an  inch  in  diam- 
eter. It  is  also  quite 
easy  to  find  the  cysti- 
cerci of  the  cat's  tape- 
worm in  the  liver  of 
the  mouse. 

Parasitic  Arthropods. 
-  The  protozoans  and 
worms  are  all  internal 
parasites,  but  among 
the  arthropods  are 
found  both  internal  and  external  feeders.  To  the  latter 
group  belong  most  of  the  mites  and  ticks  of  the  class 
Arachnida.  The  hair  mite  (Fig.  150)  is  common  in 


FIG.   367.  —  The    mite   producing   sheep  scab. 
Much  enlarged. 


328 


ANIMAL   LIFE 


human  oil  glands  supplying  the  hair.  The  microscopic 
itch  mite  buries  itself  beneath  the  skin  and  causes  the 
disease  of  itch.  Several  other  species  of  mites  affect  the 
domestic  animals  and  cause  the  falling  out  of  the  hair 
and  other  disturbances. 

The  cattle  tick  (Boophilus  boms)  affects  the  cattle  of 
the  Southern  states,  Mexico,  and  Cuba.  Like  many 
external  parasites,  it  sometimes  leaves  one  victim  to 


PIG.  368. — The  cattle  tick,  female  and  male.    Much  enlarged.     After  Howard. 

attack  another  later,  and  in  so  doing  transfers  the  germs 
of  disease  from  the  sick  to  the  healthy.  The  cattle  tick 
has  thus  been  found  to  be  the  chief  if  not  the  only  means 
of  spreading  the  fatal  Texas  fever  among  herds  of  cattle, 
and  it  is  on  this  account  that  all  cows  shipped  north  must 
first  pass  through  the  dipping  tanks  of  petroleum  or  other 
insecticidal  liquid.  Several  species  of  ticks  affect  the 
domestic  animals. 
The  lice,  of  which  there  are  more  than  forty  species 


PARASITISM 


329 


FIG.  369.  — Bed  bug.  Side  view  shows 
the  piercing  beak.  Photograph  twice 
life  size. 


living  on  birds  and  mammals,  differ  from  the  true  mites 
and  ticks  in  having  only  three  pairs  of  legs,  and  the  body 
is  divided  into  three  parts  characteristic  of  all  insects. 
Because  of  their  parasitic  habits  the  wings  have  been  lost. 
They  secure  their  food  by  sucking  the  blood  or  by  feeding 
on  the  hair  and  feathers. 
Only  three  species  affect 
man. 

The  bedbug  and  many 
of  the  flies  are  what  may 
be  termed  temporary  para- 
sites as  they  are  present 
on  the  host  only  at  inter- 
vals. Among  the  fleas, 
Pulex  irritans  is  the  one 
annoying  the  dog,  cat,  and  man.  The  eggs  are  often 
laid  on  the  hair  of  the  cat  or  dog  and  the  slender  wrig- 
gling larvae  live  in  the 
dirt  filling  the  cracks 
of  the  floor  or  similar 
places.  The  female  of 
several  species  of  mos- 
quitoes attacks  all  warm- 
blooded animals  and 
often  conveys  to  man 
serious  diseases,  such  as 
malaria,  filariosis  and 
yellow  fever. 

Many  insects  are  parasitic  during  their  larval  life,  but 
independent  during  the  adult  stage.  The  larvae  of  several 
species  of  botflies  dwell  during  the  larval  state  either  in 


FIG.  370.  — Cat  and  dog  flea  enlarged  fifteen 
tim  es .     After  Howard. 


330 


ANIMAL   LIFE 


the  alimentary  canal  or  just  beneath  the  skin  of  the  mam- 
mals.   The  young  of  the  horse  bot  dwell  in  the  stomach, 


FIG.  371.  — Anopheles,  the  parasitic  mosquito,  infecting  man  with  the  malaria 
germ.    Photograph  enlarged  three  times. 

while  those  of  the  cow  migrate,  as  soon  as  hatched,  from 
the  alimentary  canal  to  the  back,  just  beneath  the  skin, 
through  which  they  make  holes  to 
breathe  and  later  escape. 

All  of  the  ichneumon  flies,  of 
which  there  are  more  than  a  thou- 
sand species,  are  parasitic  in  other 
insects  during  the  larval  state. 
Their  presence  usually  means  death 
to  the  host.  .  They  are,  therefore, 
of  great  service  in  keeping  in  check  harmful  species,  such 
as  the  cabbage  worm,  tussock  moth,  fall  webworm,  and 
cotton  caterpillar.  Out  of  a  hundred  larvae  of  moths  and 


FIG.  372. —Larva  of  the  ox 
bot  (warble)  removed  from 
beneath  the  skin  of  the  back. 
Photograph  life  size. 


PARASITISM 


881 


FIG.  373.  —  Larva  of  the  Catalpa  sphinx  moth  frdm  which  are  issuing  the  larva* 
of  ichneumon  flies.  The  Avhite  ovoid  bodies  are  the  cocoons  in  which  the 
larvae  transform  to  adults.  Over  a  hundred  parasites  were  present  in  this  host. 
Photograph  about  life  size. 

butterflies  collected  in  late  summer  or  autumn  nearly  one 
half  will  usually  be  found  to  contain  the  parasites  of 
either  the  ichneumon  or  chalcis  flies. 

The  chalcis  flies  are  small,  and  some  species  deposit 
their  eggs  on  the  skin  instead  of  within  the  insect,  and 


FIG.  374.  —  Thalessa,  an  ichneumon  inserting  its  two-inch  ovipositor  in  a  beech  tree 
to  lay  an  egg  in  the  burrow  of  the  horn  tail,  a  wood  borer  upon  which  the  young 
ichneumon  will  feed.  The  two  curved  hairlike  supports  steady  the  ovipositor. 
Photograph. 


332 


ANIMAL  LIFE 


FIG.  375.  — Five  larvae  of  a  chalcis  fly  in  a  bunch  on  a  caterpillar.    Photograph 
nearly  twice  life  size. 


certain  species  parasitize  the  eggs  of  the  harmful  insects, 
thus  rendering  great  service.  Tachina  flies  aid  in  the 
good  work  also.  Their  minute  eggs  are 
glued  to  the  skin  of  the  host  separately 
(Fig.  26). 

In  cases  where  the  young  live  an  in- 
dependent life  and  the  adults  are  para- 
sites, marked  degeneration  often  occurs, 
which  is  especially  noticeable  among  the 
crustaceans.  Sacculina  exhibits  in  youth 
the  characteristic  features  of  its  order,  but 
after  becoming  a  parasite  on  the  crab  in 
later  life,  the  legs,  eyes,  and  mouth  parts  are  entirely  lost 
and  it  absorbs  nourishment  from  its  host  by  numerous  del- 
icate, rootlike  suckers.  Other  peculiar  crustaceans,  known 


FIG.  370.  -A  Tachin 
fly-  Photograp 

slightly  enlarged. 


PAKASITISiM 


833 


as  fish  lice,  live  as  parasites  attached  to  the  gills  or  ex- 
ternal surface  of  fish  and  other  aquatic  forms.  Of  these  the 
Lerneans  are  most  remarkable  in  respect  to  degeneration. 
They  occur  on  all  aquatic  creatures  from  the  coelenterates 
and  echinoderms  to  the  whales.  Out  of  a  dozen  codfish 
I  examined  on  the  Maine  coast,  eight  contained  one  or 


FlG.  377.  —  Nauplius  or  larva 
ofLernea  branchialis.  Pho- 
tographed through  the  micro- 
scope. 


FIG.  378.  — Adult  female  Ler- 
nea  branchialis.  The 
branched  process  at  the  left 
enables  it  to  hold  fast  in  the 
gills.  Photograph  life  size. 


more  individuals  of  Lernea  branchialis  embedded  in  the 
gills.  The  male  of  this  species  leads  an  independent  life. 
This  brief  discussion  of  parasites  shows  that  but  few, 
if  any,  of  the  species  above  the  protozoa  are  exempt  from 
having  their  bodies  made  the  feeding  ground  for  smaller 
creatures.  If  certain  species  of  insects  occur  in  vast 
numbers  one  season,  few  will  be  present  the  following 
year  owing  to  destruction  by  parasites.  The  life  of  these 
paupers  means  death  to  many  of  their  hosts,  and  so  large  a 
part  do  they  play  in  the  world  of  physical  life  that  Dr. 
Smith  says,  "  Without  them  there  would  be  no  possibility 
of  an  existing  vegetation." 


334  ANIMAL   LIFE 


24.  VANISHING  SPECIES 

The  fossil  remains  of  animal  life  embedded  in  the  rocks 
testify  that  more  than  fifty  thousand  species  have  vanished 
within  probably  thirty  million  years.  The  stone  records 
indicate  that  during  the  ancient  past  no  one  species  sur- 
vived longer  than  two  or  three  million  years,  while  some 
may  have  existed  only  a  few  thousand  years.  In  the 
earth's  youth,  the  comparatively  rapid  changes  in  climate, 
soil,  and  food,  together  with  the  appearance  of  new  ene- 
mies, made  it  necessary  that  any  species  to  win  in  the 
struggle  for  existence  should  change  its  habits  and  struc- 
ture to  harmonize  with  its  environment.  The  penalty  for 
failure  to  do  this  was  extinction.  There  is  a  continual 
warfare  in  nature  not  only  between  certain  different  species, 
but  also  among  the  individuals  of  the  same  species.  Of 
the  one  hundred  or  more  spiders  hatched  from  the  eggs  in  a 
cocoon  only  a  few  attain  full  size,  the  weaker  being  eaten 
by  the  stronger.  Of  the  million  eggs  deposited  by  a  shad, 
probably  less  than  a  score  give  rise  to  adults,  as  many  will 
die  from  lack  of  food  and  others  must  go  to  satisfy  the 
carnivorous  appetite  of  larger  fish.  Of  a  dozen  quail 
reared  in  a  single  nest,  only  a  few  of  the  more  hardy  and 
wideawake  will  be  able  to  endure  the  rigorous  winter  and 
escape  the  ever-pursuing  enemies.  The  fulmar  petrel  is 
one  of  the  most  abundant  of  birds  in  certain  regions  of  the 
seas,  but  the  female  lays  only  one  egg  yearly.  It  has 
scarcely  any  enemies.  Rabbits,  though  producing  three 
litters  of  from  four  to  six  each  in  a  season,  are  on  the  de- 
crease in  the  Eastern  States,  owing  to  the  presence  of 


VANISHING   SPECIES  335 

so  many  foxes,  dogs,  mink,  men,  and  raptorial  birds.  In 
the  Western  States  the  rabbits  have  lately  increased 
to  such  an  extent  that  public  drives  or  hunts  are  arranged, 
by  which  as  many  as  twenty  thousand  are  taken  in  a  single 
day.  This  increase  is  due  to  the  fact  that  the  wolves  and 
coyotes,  which  formerly  preyed  on  the  rabbits,  have  year 
by  year  had  their  ranks  lessened  by  the  shotgun,  the  trap, 
and  poisoned  bait.  In  parts  of  New  Zealand,  where  car- 
nivorous animals  are  few,  the  imported  rabbits  have  multi- 
plied to  such  an  extent  as  to  consume  all  the  grass,  thereby 
causing  the  sheep  to  starve  to  death.  Thus  the  ascendency 
of  one  group  of  animals  often  means  the  disappearance  of 
another.  This  is  especially  true  of  the  introduction  of  a 
parasite  into  a  new  country  where  the  hosts  have  not  be- 
come more  or  less  adapted  to  withstanding  its  attacks. 
The  smallpox  germ  introduced  into  Iceland  in  1734  killed 
more  than  half  the  population,  and  almost  equally  fatal 
results  occurred  when  the  disease  first  visited  Greenland. 

It  is  therefore  evident  that  the  extermination  of  a  species 
depends  on  several  factors,  most  important  of  which  are 
the  presence  of  numerous  enemies  and  the  lack  of  proper 
food.  During  the  age  of  man,  including  perhaps  not  much 
over  a  hundred  thousand  years,  several  species  of  verte- 
brates have  become  extinct,  among  which  are  the  huge 
mammoth  (a  near  relative  of  the  elephant),  Steller's  sea 
cow,  the  great  auk,  and  the  moas  or  giant  birds  of  New 
Zealand. 

In  1871  Colonel  Dodge  drove  for  twenty-five  miles  along 
the  Arkansas  River  through  an  unbroken  herd  of  buffalo. 
Millions  of  these  noble  animals  fed  on  the  western  plains. 
A  few  years  later  the  completion  of  the  Northern  Pacific 


336 


ANIMAL   LIFE 


FIG.  379. —The  mammoth,  the  ancestor  of  the  elephant.      From   a  painting  by 
Knight  in  the  American  Museum  of  Natural  History. 

Railroad  brought  the  hide  hunter  to  the  grazing  grounds, 
and  by  1883  scarcely  a  thousand  buffalo  were  in  existence. 
Congress  has  many  times  failed  to  do  its  duty  in  enacting 
proper  laws  for  the  preservation  of  our  animal  wealth. 

Until  a  half  century  ago  moose  were  abundant  in  the 
Adirondacks  and  many  other  wooded  regions  in  the  north- 
ern states,  but  the  ceaseless  slaughter  continuing  for  years 
unchecked  has  exterminated  the  species  in  most  of  the 
states  except  Maine,  Wyoming,  Idaho,  and  Minnesota. 
The  prong-horned  antelope  has  been  saved  from  utter 
destruction  in  most  of  the  states  it  inhabits  by  the  enact- 
ment of  proper  laws.  In  Routt  County,  Colorado,  it  is 
estimated  that  only  about  fifty  antelope  survive,  while 
fifteen  years  ago  there  were  nearly  fifty  thousand.  In  the 


VANISHING   SPECIES 


337 


same  State,  the  mule  deer  is  said  also  to  be  on  the  verge  of 
extinction.  Any  animal  valuable  for  flesh,  fur,  or  feathers 
is  destined  to  be  one  of  the  vanishing  species  unless  pro- 
tected by  law  from  its  great  enemy,  man.  The  beaver, 
celebrated  for  its  architectural 
skill  and  intelligence,  has  fled 
from  most  of  its  former  haunts  in 
the  Eastern  and  Middle  States, 
and  now  exists  only  in  small 
numbers  from  the  Rio  Grande 
in  Texas  northward  to  the  limit 
of  trees,  and  southeastward 
through  Canada  to  New'  Eng- 
land. The  fur-bearing  Alaska 
sea  lion,  wrongly  called  seal, 
which  for  many  years  furnished 
more  than  a  million  dollars' 
worth  of  sealskin  annually,  will 
within  another  decade  become 
so  few  as  to  be  of  little  com- 
mercial value  unless  the  killing  of  mothers  at  sea  is 
stopped.  In  1873  a  special  agent  of  the  government  esti- 
mated the  number  of  seals  living  on  the  Prib'ilof  Islands 
to  be  over  three  millions.  In  1890  the  number  was  con- 
sidered to  be  less  than  one  million,  and  in  1903  a  careful 
investigation  showed  that  only  about  two  hundred  thou- 
sand were  yet  living. 

Not  only  mammals,  but  likewise  birds  and  fish,  are  van- 
ishing before  the  terrific  slaughter  of  man.  The  woodcock, 
wild  turkey,  prairie  chicken,  and  wild  pigeon  abounded  in 
many  regions  a  quarter  of  a  century  ago.  To-day  the 


FIG.  330.  — The  buffalo  (bison). 
Photographed  in  the  Philadel- 
phia Zoological  Gardens. 


338  ANIMAL   LIFE 

woodcock  have  deserted  entirely  many  of  their  former 
feeding  grounds  east  of  the  Mississippi,  and  are  scarce 
everywhere.  The  wild  turkey  survive  only  in  a  few  heavily 
timbered  regions  in  Florida,  Virginia,  Pennsylvania,  Texas, 
and  perhaps  one  or  two  other  States.  The  prairie  chicken, 
once  so  numerous  on  the  western  plains,  can  not  last  much 
beyond  another  decade,  and  the  wild  pigeon  was  thought 
to  be  practically  extinct  in  1899,  but  a  few  scattered  flocks 
have  since  been  discovered.  The  enormous  numbers  of 
pigeons  present  in  the  Eastern  States  forty  years  ago  is 
clearly  shown  by  Audubon's  description  of  them  as  ob- 
served in  Kentucky. 

"  Let  us  now  inspect  the  places  of  nightly  rendezvous. 
.  .  .  My  first  view  of  it  was  about  a  fortnight  subsequent 


FIG.   381.  — The    wild   pigeon    (Ec-topisteus    migratorius).      Photographed   in   the 
Academy  of  Natural  Sciences,  Philadelphia.    One  sixth  life  size. 

to  the  period  when  they  had  made  a  choice  of  it.  ...  As 
the  period  for  their  arrival  approached,  their  foes  anxiously 
prepared  to  receive  them.  .  .  .  The  sun  was  lost  to  our 
view,  yet  not  a  dozen  had  arrived.  Everything  was  ready, 


VANISHING   SPECIES  339 

and  all  eyes  were  gazing  on  the  clear  sky,  which  appeared 
in  glimpses  through  the  tall  trees.  Suddenly  there  burst 
forth  a  general  cry,  '  Here  they  come.'  .  .  .  Thousands 
were  soon  knocked  down  by  the  pole  men.  The  birds 
continued  to  pour  in.  The  fires  were  lighted  and  a  magnifi- 
cent as  well  as  wonderful  and  almost  terrifying  sight  pre- 
sented itself.  The  pigeons  arrived  by  thousands,  alighted 
everywhere,  one  above  another,  until  solid  masses  as  large 
as  hogsheads  were  formed  on  the  branches  all  around. 
Here  and  there  the  perches  gave  way  under  the  weight 
with  a  crash,  and  falling  to  the  ground  destroyed  hundreds 
of  birds  beneath,  forcing  down  the  dense  groups  with  which 
every  stick  was  loaded.  It  was  a  scene  of  uproar  and 
confusion.  I  found  it  quite  useless  to  speak  or  even  to 
shout  to  those  persons  who  were  nearest  to  me.  Even 
the  reports  of  the  guns  were  seldom  heard,  and  I  was  made 
aware  of  the  firing  only  by  seeing  the  shooters  reloading. 

"  No  one  dared  to  venture  within  the  line  of  devasta- 
tion. .  .  .  The  pigeons  were  constantly  coming,  and  it 
was  past  midnight  before  I  perceived  a  decrease  in  the 
number  of  those  that  arrived." 

The  investigations  of  Hornaday,  as  cited  in  a  previous 
chapter,  show  that  many  species  of  birds  are  being  so  per- 
secuted by  the  egg  hunters,  the  small  boy,  and  the  cat, 
that  their  numbers  have  been  lessened  one  half  within 
fifteen  years,  and  soon  we  may  expect  several  species  to 
become  extinct  unless  through  education  public  sentiment 
is  changed. 

The  supply  of  alligators  has  decreased  about  ninety- 
eight  per  cent  since  fashion  smiled  on  belts,  pocket-books, 
and  hand  bags  made  of  alligator  hide.  If  the  demand  for 


340  ANIMAL  LIFE 

tortoise-shell  articles  continues  on  the  increase  another 
decade  or  two,  the  hawkbill  turtle  will  share  the  fate  of 
the  buffalo.  The  salmon,  trout,  and  lobster,  once  supply- 
ing millions  of  dollars'  worth  of  fine  food  annually,  are 
reported  to  be  decreasing  in  an  alarming  manner  owing  to 
the  recklessness  with  which  lax  laws  permit  them  to  be 
caught.  Of  the  twenty-eight  rivers  formerly  inhabited 
by  the  salmon,  only  eight  now  contain  them,  and  in  one 
district  where  in  1896  three  hundred  thousand  cases  of 


FIG.  382.  — The  brook  trout. 

salmon  were  put  up,  scarcely  any  fish  were  taken  three 
years  later.  While  the  brook  trout  will  probably  always 
be  cultivated  in  ponds,  where  its  finer  qualities  degener- 
ate, there  is  scarcely  a  possibility  of  its  continuance  in  the 
unprotected  forest  streams  longer  than  a  decade  or  two. 

The  government  authorities  of  the  various  states  as  well 
as  of  the  United  States  within  recent  years  have  become 
aware  of  the  fact  that  in  order  to  preserve  the  vast  wealth 
of  our  country  represented  by  wild  animal  life,  stringent 
protective  laws  and  an  enlightened  public  sentiment  must 
be  created.  The  recreation  and  sport  afforded  by  the 
legitimate  hunting  of  wild  game  is  a  great  conserver  of 


VANISHING   SPECIES  341 


FIG.  383.  —  The  lobster.    Photograph  one  fifth  life  size. 

nervous  energy,  and  when  statistics  show  the  millions  of 
dollars  bound  up  in  the  untamed  fish,  fowl,  and  beast, 
there  can  be  no  doubt  about  the  wisdom  of  spending  a 
large  amount  of  money  to  maintain  this  wealth  in  forest 
and  stream.  The  value  of  our  fish  products  annually  is 
fully  fifty  million  dollars.  The  annual  government  appro- 
priation for  the  maintenance  of  the  fish  industry  is  a  half 
million  dollars.  From  July,  1901,  to  July,  1902,  the  bureau 
of  fisheries  distributed  eggs  and  young  fish  to  the  number 
of  1,414,523,374.  In  addition,  81,020,000  young  lobsters 
were  planted  in  favorable  localities  along  the  seacoast. 
Thus  by  the  aid  of  the  State  and  the  United  States  Fish 
Commissions  hundreds  of  streams  have  been  stocked  with 
trout,  bass  and  other  game  fish,  and  lobster  fishing  has 
been  made  a  productive  industry  in  many  regions  along 
the  coast. 

When  boys  and  girls  as  well  as  men  and  women  realize 
that  every  act  tending  toward  the  preservation  of  our  bene- 
ficial wild  animals  manifests  true  patriotism,  history  will 
record  a  full  century  without  the  extinction  of  a  single 
valuable  species  of  animal  life. 


342  ANIMAL  LIFE 

25.   ORIGIN  OF  THE  DIVERSE  FORMS  OF  ANIMAL  LIFE 

A  study  of  the  universe  and  of  the  rocks  forming  the 
crust  of  the  earth  shows  that  conditions  were  such  many 
millions  of  years  ago  that  no  life  could  have  existed  on  this 
planet.  It  is  therefore  evident  that  living  things  at  some 
time  in  the  past  must  either  have  been  developed  from  life- 
less material  or  reached  the  earth  from  some  other  heavenly 
body.  Scientists  find  no  evidence  in  favor  of  the  latter 
theory,  and  we  are  therefore  forced  to  believe  that  at  some 
period  after  the  surface  of  the  earth  became  cool,  spon- 
taneous generation  occurred,  i.e.,  a  particle  of  lifeless  earth 
was  transformed  into  a  living  thing. 

The  conception  of  the  ancient  as  well  as  some  of  the 
more  modern  philosophers  in  regard  to  the  origin  of  animals 
is  entirely  erroneous.  Aristotle  held  that  some  animals 
spring  from  putrid  matter,  that  certain  insects  develop 
from  dew,  that  worms  originate  in  the  mud  of  wells,  that 
fleas  arise  from  very  small  portions  of  corrupted  matter, 
and  bugs  proceed  from  the  moisture  on  animal  bodies,  and 
lice  from  the  flesh  of  other  creatures.  Van  Helmont,  of 
the  seventeenth  century,  gives  detailed  directions  for 
creating  mice  out  of  wheat  and  stagnant  water.  The 
learned  Alexander  Ross,  about  the  year  1700,  declares 
there  is  no  doubt  that  worms  are  generated  from  cheese 
and  that  butterflies,  locusts,  grasshoppers,  snails,  eels,  and 
such  like  originate  from  putrid  matter. 

Before  the  days  of  the  compound  microscope  and  care- 
ful scientific  research,  spontaneous  generation  was  thought 
to  be  going  on  continually,  but  by  numerous  carefully  con- 
ducted experiments  of  Spallanzani,  Schultze,  Schwann, 


ORIGIN  OF  THE  DIVERSE  FORMS  OF  ANIMAL  LIFE      343 

and  Pasteur  it  was  demonstrated  about  fifty  years  ago  that 
spontaneous  generation  does  not  occur  under  present  con- 
ditions in  this  world.  All  animals  originate  from  their 
parents  by  means  of  fission,  spore  formation,  budding,  or 


FIG.  384.  —  Amoeba  showing  formation  of  two  animals  from  one  by  fission. 

eggs.  Fission,  consisting  in  the  division  of  the  animal 
into  two  parts,  is  common  among  the  Protozoa  and  occurs 
in  a  few  species  of  worms.  Spore  formation  may  be  seen 
in  some  of  the  Protozoa,  such  as  the  malarial  parasite,  in 
which  case  the  animal  forms  a  cyst  or  thick  coat  around 


344 


ANIMAL   LIFE 


itself  and  divides  into  several  fragments.  The  cyst  then 
burst,  and  each  fragment  or  spore  becomes  a  separate 
animal.  As  noted  in  a  previous  chapter,  budding  takes 
place  in  the  hydra  and  many  other  coelenterates  and  in  a 
fow  worms.  Reproduction  by  eggs  occurs  in  all  species 

above  the  protozo- 
ans. The  eggs  and 
spores  of  some  of 
the  microscopic  ani- 
mals are  so  small 
as  to  require  very 
high  magnifying 
power  to  define  them 
clearly,  and  when 
dry  are  capable  of 


inthe  air  by  currents 

thereby  gaining  access  to  open  vessels  of  water  or  other 
fluids  suited  to  their  development.  Until  fifty  years  ago 
people  thought  that  broth  or  milk  boiled  in  an  air-tight 
jar  sometimes  spoiled  because  particles  of  the  materials 
were  transformed  into  minute  living  bodies.  At  present 
it  is  well  understood  that  the  life  in  the  sealed  and  heated 
jars  was  due  to  minute  germs  or  spores  of  plant  life,  called 
bacteria,  some  of  which  are  not  killed  by  being  boiled  a 
half  hour. 

Up  to  the  present  time  nearly  a  half  million  different 
kinds  or  species  of  animals  have  been  described,  and  more 
than  a  hundred  new  species  are  discovered  every  year,  so 
that  it  is  probable  that  there  are  no  less  than  a  million 
species  of  animals  dwelling  on  this  planet.  That  a  pair  of 


ORIGIN  OF  THE  DIVERSE  FORMS  OF  ANIMAL  LIFE      345 


each  of  these  was  created  direct  from  lifeless  material  seems 
very  improbable,  though  until  1859,  when  Charles  Darwin 
published  his  "  Origin  of  Species,"  this  was  generally  be- 
lieved. The  Bible  describes  briefly  the  creation  of  the 
various  groups  of 
animals  on  several 
successive  days. 
These  days  instead 
of  being  twenty- 
four  hours,  as  for- 
merly understood, 
are  now  considered 
to  have  been  long 
periods  of  time, 
each  equaling  sev- 
eral million  years. 
The  earth's  surface 
was  once  entirely 
covered  with  water 
holding  in  solution 
or  suspension  large 
quantities  of  min- 
eral matter,  which  settling  to  the  bottom  from  time  to  time 
hardened  into  strata  (layers)  of  rock.  The  skeletal  portions 
of  the  animals  dying  also  dropped  to  the  bottom,  and  oft- 
times  left  the  indelible  impressions  of  their  bodies  in  the 
forming  rock,  or  the  skeletal  structure  was  itself  replaced 
with  stone  (fossilized).  By  contraction  of  the  earth's  crust 
certain  portions  were  forced  up  out  of  the  water  and  made 
ready  for  habitation  by  land  animals.  These  coming  to  the 
water  to  drink  or  rushing  into  the  lakes  to  escape  from  their 


FIG.  386.  —  Bacteria  causing  consumption  (tubercu- 
losis) ;  six  or  seven  germs  resembling  minute  rods 
are  present.  Photograph  magnified  one  thousand 
diameters. 


346 


ANIMAL   LIFE 


enemies  sometimes  perished,  and  their  skeletons  were  like- 
wise entombed  in  the  sediment-forming  rock  and  there 
became  fossilized.  Therefore,  each  successive  stratum  or 
layer  of  rock  containing  the  remains  of  the  life  of  former 
ages  serves  as  the  leaf  of  a  book  giving  a  description  of  the 

animate  world  be- 
fore the  era  of  man. 
By  careful  compu- 
tation scientists 
have  determined 
that  life  has  proba- 
bly existed  on  the 
earth  for  a  period 
of  from  twenty  mil- 
lion to  one  hundred 
million  years.  The 
fossil  remains  show 
that  the  inverte- 
brates lived  here  more  than  a  million  years  before  there 
were  any  vertebrates;  the  fish  preceded  the  amphibians 
by  several  million  years,  while  as  much  more  time  elapsed 
before  the  advent  of  reptiles,  which  dwelt  here  at  least 
two  or  three  million  years  before  the  appearance  of  birds. 
There  is  evidence  indicating  that  man  has  been  on  the 
earth  from  fifty  thousand  to  a  hundred  thousand  years, 
and  it  is  possible  that  he  has  been  here  even  a  million 
years. 

"  From  lower  to  higher, 
From  simple  to  complete, 
This  is  the  pathway  of  eternal  feet ; 
From  earth  to  lichen, 


FIG.  387.  —  A  piece  of  rock  containing  the  fossil  re- 
mains of  several  animals.  Photographed  in  Am- 
erican Museum  of  Natural  History. 


ORIGIN  OF  THE  DIVERSE  FORMS  OF  ANIMAL  LIFE     84? 

From  herb  to  towering  tree, 
From  cell  to  creeping  worm, 
From  man  to  what  shall  be ; 
This  is  the  lesson  of  all  time, 
This  is  the  teaching  of  the  voice  sublime." 

The  sequence  of  forms  in  the  successive  rock  strata 
makes  it  evident  that  under  the  stress  of  a  rapidly  changing 
environment  certain  individuals  of  a  species  changed  in 
habit  and  structure  so  as  to  persist  in  the  struggle  among 


FIG.  388.  —  Photograph  of  the  fossil  feet  of  three-toed  horses  iu  the  Museum  of 
Natural  History. 

associates  for  food,  and  thus  gave  origin  to  a  new  variety 
or  kind  of  animal,  while  those  of  the  species  which  did  not 
change  to  a  more  advantageous  habit  and  structure  be- 
came extinct.  For  instance,  records  clearly  show  that  the 


B48  ANIMAL  LIFE 

ancestor  of  our  horse  was  a  three-toed  uigulate  scarcely 
larger  than  a  sheep  and  with  teeth  adapted  to  feed  on  succu- 
lent vegetation,  such  as  the  warm,  moist  climate  of  those 
early  days  afforded.  As  the  ground,  then  wet  and  swampy, 
became  hard,  and  the  juicy  vegetation  gave  way  to  the 
dryer  grasses,  the  lateral  toes  became  shorter  in  certain 


FIG.  389.  —  Skeleton  of  Mesohippus  bairdi,  the  three-toed  ancestor  of  our  horse. 
This  animal  was  about  the  size  of  a  sheep.    After  Farr. 

individuals,  and  the  third  digit  grew  longer  and  stronger, 
thus  enabling  them  to  escape  their  carnivorous  pursuers, 
while  all  those  individuals  whose  limbs  and  teeth  did  not 
vary  so  as  to  aid  them  to  escape  the  increasing  carnivorous 
animals  and  masticate  the  dry  grasses,  were  exterminated. 
Thus  age  after  age  those  horses  whose  lateral  toes  became 
smaller  while  the  third  one  grew  longer,  giving  them  greater 
speed,  persisted  and  multiplied,  but  those  with  large,  lateral 


ORIGIN  OF  THE  DIVERSE  FORMS  OF   ANIMAL  LIFE     349 


toes  as  an  encumbrance  fell  prey  to 
their  pursuers.  This  process  of  de- 
veloping new  species  is  called  evolu- 
tion by  variation  and  natural  selection. 
The  ancestor  of  the  three-toed  horses 
were  four-toed  animals  whose  remains 
are  found  in  the  layers  of  rock  be- 
neath those  containing  the  three-toed 
ones.  By  this  process  of  variation 
and  natural  selection  the  four-toed 
forms  were  derived  from  a  five-toed 
mammal  with  such  a  generalized  FIG.  390. -Photograph of 

t  foot  of  four-toed  horse 

Structure   that  Other     Of     itS     progeny  in  American  Museum  of 

Natural  History. 

developed  into  sheep,  cows,  and  deer 

in  accordance  with  the  various  foods  and  changing  factors 


FIG.  391.  —  After  Matthews  in  Guide  Leaflet  of  American  Museum  of  Natural  History. 


350 


ANIMAL   LIFE 


in  nature  to  which  they  were  subjected.  Thus,  by  varia- 
tion and  natural  selection  numerous  and  widely  different 
kinds  of  animals  arose. 

Variation  in  the  individuals  of  certain  species,  and  there- 
fore evolution,  is  occurring  at  the  present  time,  but  much 


Fro.  392. — The  four-toed  horse  restored  from  a  study  of  its  fossil  skeleton.    From 
Guide  Leaflet  of  the  Museum  of  Natural  History,  New  York. 

more  slowly  than  during  the  world's  infancy,  when  climate, 
food,  and  other  factors  were  changing  more  rapidly.  An 
observer,  seeing  for  the  first  time  the  very  dark  and  very 
light  forms  only  of  the  Catalpa  caterpillar,  would  at  a 
glance  declare  them  two  different  species,  but  after  find- 
ing specimens  with  all  the  gradations  in  shade  from  light 
to  dark  (Fig.  394),  he  would  be  forced  to  consider  the  two 
unlike  individuals  to  belong  to  the  same  species.  If,  in  the 
future,  the  four  intervening  forms  shown  in  the  figure  be- 
come extinct  and  the  adults  of  number  one  and  number 
six  differ  as  widely  as  the  larvse  and  remain  constant  in 


ORIGIN  OF  THE  DIVERSE  FORMS  OF  ANIMAL  LIFE      351 

their  characteristics,   scientists    would    be  warranted  in 
recognizing  the  two  forms  as  separate  species. 

A  species  of  moth  of  the  genus  Saturnia,  brought  from 
Texas  to  Switzerland,  where  the  young  fed  on  the  European 


PIG.  393.  —  The  Mastodon,  an  early  ancestor  of  the  elephant  and  long  since  extinct. 
From  a  painting  by  Knight  in  the  American  Museum  of  Natural  History. 

walnut,  presented  after  one  generation  such  marked  differ- 
ences from  the  same  species  whose  young  fed  in  Texas  on 
the  black  walnut,  that  entomologists  gave  it  a  new  name. 
The  brine  shrimp,  Artemia  salina,  lives  in  slightly  brackish 
water,  while  Artemia  milhauseni  occurs  only  in  very  salt 
water.  If  salt  be  gradually  added  to  the  vessel  containing 
the  former  species,  it  will  in  a  few  generations  during  the 
months  of  a  single  summer,  transform  into  the  latter  species. 
Likewise,  Artemia  milhauseni  will,  in  a  few  months,  change 


352 


ANIMAL  LIFE 


into  Artemia  saUna  upon  the  gradual  addition  of  fresh 
water.  The  crustaceans  and  fish  of  the  Mammoth  Cave, 
though  differing  greatly  in  certain  features  from  the  forms 


FIG.  394.  —  Variation  in  the  Catalpa  caterpillar.     Photograph  natural  size. 

in  the  waters  just  outside,  give  unmistakable  evidence  of 
being  their  direct  descendants. 

Other  evidences  of  evolution  are  furnished  by  rudimen- 
tary structures,  which  are  present  in  all  of  the  higher  verte- 
brates. Some  of  the  lizards,  having  only  one  pair  of  legs, 
have  rudiments  of  the  other  pair  beneath  the  skin.  The 
rudiments  of  the  hind  legs  in  the  Python  are  apparent  ex- 
ternally. No  functional  hind  limbs  are  present  in  any  of 
the  whales,  but  several  species  possess  small  structures 


ORIGIN  OF  THE  DIVERSE  FORMS  OF  ANIMAL  LIFE      853 


beneath  the  skin  in  the  position  of  the  hind  limbs.  Teeth 
are  present  in  the  jaws  of  the  whalebone  whales,  but  they 
never  appear  above  the  surface,  and 
the  young  of  the  ruminants  have 
buried  in  the  gums  minute  upper 
incisors,  though  they  do  not  de- 
velop into  functional  teeth  in  the 
adults.  The  vermiform  appendix, 
occurring  in  man  and  the  anthro- 
poid apes,  is  of  no  use,  but  in  their 
ancestors  it  may  have  played  an 
important  part  in  digestion,  as  the 
corresponding  portion  of  the  ali- 
mentary canal  does  yet  in  the  rab- 
bit, groundhog,  and  other  forms. 
The  splint  bone,  about  ten  inches 
long  on  either  side  of  the  lower  part 
of  the  horses'  limb,  serves  no  useful 
purpose  now.  All  of  these  useless 
structures  clearly  indicate  that  they 
were  of  larger  size  in  the  far-off  an- 
cestors in  whom  their  presence  was 
of  great  use. 

Still  further  testimony,  favoring 
a  belief  in  evolution,  is  given  by  the 
study  of  Embryology  which  deals 
with  the  development  of  the  young 
from  the  egg.  In  very  young  stages  the  higher  verte- 
brates are  seen  to  resemble  the  adult  forms  of  some  of  the 
lower  animals.  The  chick,  when  taken  from  an  egg 
incubated  for  three  days,  is  found  to  have  gill  slits  and 


FIG.  395.  — Skeleton  of  the 
fore  limb  of  the  horse. 
sc,  shoulder  blade ;  h,  hu- 
merus  ;  r,  radius  ;  ua, 
ulna;  m3,  third  metacar- 
pal;  m4,  splint  bone  or 
fourth  metacarpal ;  pt 
phalanges.  From  Davi- 
son's  "  Mammalian  Anat- 
omy." 


354 


ANIMAL   LIFE 


gill  arches  and  an  entire  circulatory  system,  strikingly 
similar  to  the  same  structures  in  the  fish.  The  brain  is 
fishlike  also.  In  some  young  birds  taken  from  the  egg, 


FlG.   396.  — Fore  limbs  of  vertebrates  showing  similarity  of  structure.     A,  sala- 
mander ;  B,  turtle  ;  C,  very  young  bird  ;  Z>,  adult  bird  ;  E,  dog ;  F,  man. 

the  wing  strongly  resembles  in  structure  the   limb  of  a 
lizard. 

These  facts,  cited  in  the  preceding  paragraphs  together 
with  much  other  information  discovered  by  the  zoologist 
and  geologist,  lead  to  the  conclusion  that  at  first  there 
existed  on  earth  only  a  few  forms  of  simple  life  similar  to 
the  amoeba,  and  from  these  acted  on  by  the  rapid  changes 
of  climate,  soil,  water,  and  food,  have  arisen  all  the  varied 
forms  of  animal  life. 


INDEX  AND  GLOSSARY 


Adaptations,  311-323. 

Adder,  214,  216. 

Air  bladder,  196,  198. 

Air  sacs  of  birds,  227. 

Alligator,  221,  339. 

Alternation  of  generations,  172, 

173. 

Amblys'toma,  200,  201,  302. 
Ambula'cral,  162. 
Ameiu'rus,  190. 
Ammocoe'tes,  186,  300. 
Amoa'ba,  179-182,  324. 
Amphib'ia  (Gr.  amphi,  both,  and 

bios,  life),  27,  199-211. 
eggs  of,  294-296. 
Anaconda,  220. 
Anat'omy,  11. 
Anem'one,  174. 
Angle  worms,  152-154. 
Anguillu'la,  155. 
Animalcule,    a  minute    animal, 

178,  180. 
Annulat'a  (L.  annulus,  ring),  25, 

150-154. 
Anodont'a,  143. 
Ano'lis,  212. 
Anoph'eles,  41,  42,  182. 
Ant-eater,  263,  264. 
Antelope,  336. 
Anten'nae,  32,  68,  120,  307. 
Anthon'omus,  108,  109. 
Anthrenus,  113,  114. 
Anthropoid  apes,  281. 
Ant-lion,  117. 
Ants,  24,  56-57.  . 

cows  of,  98. 
Anu'ra,  204. 


Apes,  281. 

Aph'idse,  95. 

Aphis,  97. 

Apple  tree  borer,  24,  111. 

worm,  87. 

AquaVic,  dwelling  in  the  water. 
Aquaria,  19. 
Ar&ch'nida  (Gr.  arachne,  spider)  < 

26,  125-132. 
Arbac'ia,  164. 
Archaeop'teryx,  227. 
Argi'ope,  130. 
Armadillo,  264. 
Armored  scales,  103. 
Army  worm.  24,  48,  85. 
Arte'mia,  351. 
Ar  throp'  o  da  (Gr.  arthron,  joint 

and  poda  feet),  26,  30-40. 

parasitic,  327-333. 
Ascaris,  325. 
Asparagus  beetles,  24. 
Aspidiotus,  98-102. 
Assassin  bugs,  105. 
Aste'rias,  161-165. 
Audubon  society,  24. 
Auricle,  the  cavity  of  the  heart 

which    receives    the    blood, 

289. 

Aves,  27,  226-261. 
Ax'olotl,    larva   of    the    Ambly- 

stoma  mexicanum,  209,  302. 

Baboons,  281. 
Bacteria,  344,  345. 
Baltimore  oriole,  24,  235. 
Bark  beetle,  24,  109. 
Bark  lice,  98-104. 


355 


356 


INDEX  AND   GLOSSARY 


Barnacles,  139,  140,  299. 
Bats,  273,  274. 
Bead  snake,  216. 
Beans,  insects  affecting,  278,  279. 
Bear,  278,  279. 
Beaver,  337. 
Bee,  eye  of,  310. 
Bee  keeping,  23. 
Bee  martin,  232. 
Bees,  52-55. 
Beetles,  107-115. 
Bedbug,  24,  104. 
Bell  animalcule,  180. 
Beneficial  insects,  47,  48,  51-56. 
Bl'nary  fission,  a  method  of  re- 
production in  which  the  or- 
ganism divides  into  two  equal 
parts,  179,  182. 
Bi61'ogy,  the  study  of  plant  and 

animal  life,  11. 
Bird  day,  24. 

Bird,  external  features,  229. 
Birds,  226-261. 

decrease  in,  227. 

destruction  of,  255-257,  339. 

eggs  of,  234. 

food  of,  24. 

in  relation  to  insects,  258. 

migration  of,  24,.  260. 
Bison,  266. 
Blackbirds,  236. 
Black  crab,  116. 
Black  snake,  214,  216. 

eggs  of,  293. 
Black  swallowtail,  72. 
Bladder  worm,  159. 
Blind  crayfish,  141. 
Blissus  leucop'terus,  105. 
Blowfly,  46. 
Bluebird,  243,  248,  259. 
Blue  crab,  138. 
Blue  sharks,  188. 
Boa  constrictor,  220,  221. 
Bobolink,  235. 


Bobwhite,  318. 
Boll  worm,  23. 
Bonibyc'idae,  74. 
Bones  of  bird,  354. 

of  cat,  290,  291. 

of  dog,  354. 

of  horse,  266,  353. 

of  man,  354. 

of  salamander,  354. 

of  turtle,  354. 
Bony  fish,  189. 
Borer,  apple  tree,  111. 

locust,  111. 

maple,  112. 

peach  tree,  89,  90. 

pine  tree,  112. 

Borers,     certain     insect     larvse, 
mostly  of  beetles  and  moths, 
dwelling  in  trees,  89. 
Botflies,  48-50,  330. 
Box  tortoise,  222. 
Brain  of  cat,  287,  288. 

mammals,  290. 
Breeding  of  amphibians,  207. 
Brine  shrimp,  351. 
Brittle  star,  166. 
Brontosau'rus,  226. 
Brush-footed    butterflies,     those 
with  imperfect  and  hairy  fore- 
legs, 69. 
Buc'cal,  179. 
Buffalo,  266,  335,  336,  337. 

moth,  24,  113. 
Bufo,  207. 
Bugs,  91. 

Bulletins  and  circulars  of  Agri- 
cultural Department  of  U.  S., 
23,  24. 

Bull  frog,  205. 
Bull  head,  189. 
Bumble  bee,  54,  306. 
Butterflies,  68-73. 
Butterfly ,  protective  resemblance, 
313. 


INDEX   AND   GLOSSARY 


357 


Cabbage  butterfly,  71. 
fly,  47. 
worms,  67,  72,  73. 

Cabinets  for  insects,  17. 

Caddis  fly,  311. 

Caeca  (se  ka)  (L.  ccecus,  blind), 
163. 

Camel,  268,  271. 

Canidae,  277. 

Canker  worms,  two  species  of 
moth  larvae  which  destroy 
the  foliage  of  fruit  trees,  24, 
85,  86,  258. 

Car'apace,  the  dorsal  part  of  the 
hard  shell  of  crustaceans  and 
turtles,  133,  222. 

Caribou,  267. 

Carniv'ora  (L.  caro,  flesh,  and 
voro,  devour),  28,  275-280. 

Carpet  beetle,  24,  113. 

Cartilaginous  fish,  187-189. 

Catal'pa  caterpillar,  350,  352. 

Catalpa  moth,  47,  64,  65. 

Catamount,  276. 

Catbird,  240,  244,  258. 

Caterpillar,  the  larva  of  a  moth 
or  butterfly,  74. 

Catfish,  189,  190. 

Cats,  276. 

Cattle,  266. 

Cattle  tick,  328. 

Cave  animals,  308. 

Cave  fishes,  192. 

Cedar  bird,  240,  242,  258. 

Cell,  a  microscopic  portion  of 
semifluid  life-substance  called 
protoplasm,  usually  sur- 
rounded by  a  thin  membrane 
and  containing  a  nucleus, 
178,  289,  293,  294. 

Centiped,  18,  24,  132. 

Cerambyc'idae,  111. 

Ceta'cea  (L.  cetus,  whale),  28, 
264. 


Chalcis  flies,  67,  68,  331. 

Chalk  formers,  183. 

Chameleon,  212. 

Chatterers,  240. 

Chelo'nia,  222-225. 

Chickadee,  242,  258,  259. 

Chimney  swift,  244,  249,  250. 

Chimpanzee,  282. 

Chinch  bug,  12,  105. 

Chipmunks,  270. 

Chipping  sparrows,  238,  239. 

Chippy,  238. 

Chirop'  ter  a  (Gr.  cheir,  hand,  and 
pteron  wing),  28,  273,  274. 

Ch lor 'e tone,  a  one  per  cent  solu- 
tion added  to  from  five  to 
ten  times  as  much  water 
renders  aquatic  animals  un- 
conscious, 21,  210. 

Chloroform,  19. 

Chrys'alid,  the  pupal  stage  of  a 
butterfly,  71. 

Cica'da,  92-95,  298. 

Clams,  142,  143. 

Class,  26. 

Classification  of  animals,  25-29. 

Clavicorn  beetles,  113. 

Clear-winged  moths,  89,  90. 

Click  beetles,  113. 

Clothes  moth,  24,  88,  89. 

Clover  seed  midge,  61. 

Clupea,  190,  191. 

Cobra,  220. 

Coc'cidae,  98. 

Coccinel'lidaa.  114. 

Cochineal  insect,  103. 

Cockroaches,  24,  38. 

Co  coon',  the  case  formed  of  soil, 
hair,  silk,  or  other  material, 
in  which  many  insects  pass 
the  pupal  stage,  77,  88,  90, 
331. 

Coddling  moth,  23,  87,  88,  125 

Codfishes,  193. 


858 


INDEX  AND   GLOSSARY 


Ccelenterata  (se  len'  ter  a'ta)  (Gr. 
koilos,  hollow,  and  enteron, 
intestine),  25,  167,  175. 

Cceloine  (se'lome),  body  cavity, 
157,  168. 

Cold-blooded  animals,  196. 

C5l  e  op'  te  ra  (Gr.  koleos,  sheath, 
and  pteron,  wing),  27,  107, 
115. 

Commen'salism,  177. 

Condor,  249. 

Congo  snake,  203. 

Conjuga/tion,  a  process  of  union 
whereby  protoplasm  is  trans- 
ferred from  one  organism  to 
another,  180. 

Cooper's  hawk,  251,  253. 

Copperhead,  218,  219. 

Coral,  175. 

Corn  worm,  84. 

Cotton  boll  weevil,  12,  23,  108. 

worm,  84. 
caterpillar,  68. 
insects  affecting,  23. 

Cow  bird,  236. 

Coyotes,  277. 

Crabs,  136-138. 

Cranberries,  insects  affecting,  23. 

Crane,  254. 

Crane  flies,  44. 

Crawfish,  135,  136. 

Crayfish,  135,  136. 

Creation  of  animals,  342-354. 

Cricket,  3G,  37. 

Crinoids,  166. 

Crocodilia,  221,  222. 

Crotalidffi,  216. 

Croton  bug,  38. 

Crows,  233,  235. 

Crnsta'cea  (L.  crusla,  crust),  26, 
133-141. 

Crustaceans,  metamorphosis  of, 
299,  300. 

Cryptobran'chus,  203. 


Cuckoos,  247,  251,  258. 

Cucumber  beetles,  24. 

Culex,  39,  41,  42,  44. 

Curcu'lio,  107. 

Currant  saw  fly,  58. 

Cuttlefish,  149. 

Cutworms,  82-84. 

Cy'anide  jar,  19. 

Cyclpstom'ata,  185-187. 

Cypris,  139. 

Cysticercus  (sis  ti  sur'  kus)  (Gr. 
kystis,  bladder,  and  kerkos, 
tail),  the  larval  stage  of  a 
tape  worm,  159,  296,  327. 

Damsel  flies,  119,  120. 
Daphnia,  139. 
Deer,  267,  268. 
Desmognathus,  201,  203. 
Diapherom'era,  314. 
Diaphragm,  285. 
Digitigrade.  266. 
Digits,  265,  292. 
Diaspis,  rosse,  103. 
Digestive  system. 

Cat,  285. 

Crayfish,  134. 

Fish,  197,  198. 

Frog,  209. 

Honey  bee,  53. 

Locust,  123. 
Dipnoi,  185,  195. 
Diplodocus,  226. 
Drp'tera  (Gr.  di,  two,  and  ptera, 

wings),  27,  39-51. 
Disease,  insect  carriers  of,  24. 
Dobson,  116. 
Dog-day  fly,  94. 
Dogfish,  188. 
Dogs,  277. 
Dolphins,  264. 
Dinosau'ria,  225. 
Downy  woodpeckers,  247. 
Dragon  flies,  118. 


INDEX  AND   GLOSSARY 


359 


Drone  fly,  48. 
Drones,  52,  55. 
Duck  bill,  261. 
Duck  mole,  261,  262. 

Eagles,  248,  249,  252,  257. 
Ear,  199,  307,  308. 
Earthworms,  152-154. 
Echid'na,  262,  263. 
Echinoidae,  165. 

Echinoder'mata    (  Gr.     echinos, 
hedgehog,  and  derma,  skin), 
25,  161-167. 
Economic  zoology,  12. 
Ec'toderm  (Gr.  ectos,  outside,  and 

derma,  skin),  168. 
Ectopisteus  migratorius,  338. 
Edenta'ta,  27. 
Eel,  electric,  312. 

lamprey,  185. 

mud,  204. 
Eggs,  293-296. 

of  amblystoma,  203. 

of  birds,  234. 

of  Lepidoptera,  90. 

of  moth,  297. 
Egret,  255. 

ElaVmobran'chii,  185,  187-189. 
Elater'idse,  113. 
Electric  eel,  312. 
Electric  fish,  189. 
Elephant,  268,  269,  272. 
Elk,  267,  269. 

El'ytra,  pleural  of  el'ytron. 
El'ytron  (Gr.  elytron,  case),  the 
thickened   anterior  wings  of 
beetles  and  some  other  insects. 
Em'bryo,  294,  303. 
Encysted,  182. 

Ephemer'ida(Gr.  ephemeras,  last- 
ing a  day),  26,  117. 
En'doderm,  168. 
English  sparrow,  237,  294. 
EntomSs'traca,  299. 


Equipment,  14. 

Evolution  of  animals, 342-354. 

Eye  of  cat,  288. 

fish,  198. 

insects,  120. 

locust,  34. 
Eyes,  308,  310. 

Fall  web  worm,  64. 

Families,  28. 

Feeling  in  animals,  303-306. 

Fel'idae,  276. 

Fertilization,  172. 

Fiddler  crabs,  137. 

Fig  culture,  24. 

insect,  61. 
Filaria,  325. 
Finches,  236. 
Firefly,  112. 
Fish,  185-199. 
Fish,  characteristics  of,  196. 

hearing  in,  307. 

lice,  333. 

products,  value  of,  341. 
Fission,  179. 
Flatfish,  194. 

Flatworms,  157-161,  326,  327. 
Fleas,  61,  329. 
Flicker,  246,  250. 
Flies,  24,  39-51. 
Flounders,  194,  195. 
Flycatchers,  230-232. 
Flying  fish,  192. 
Flying  foxes,  273. 
Food  of  nestling  birds,  24. 
Forest  tent  caterpillar,  78,  81. 
Forest  snail,  148 
Forests,  insects  affecting,  24. 
For  m&l'de  hyde,  18. 
Formaline,  18. 

Forelimbs  of  vertebrates,  354. 
Fossil  animals,  225,  345-350. 

birds,  227. 
mammals,  265- 


360 


INDEX   AND   GLOSSARY 


Foxes,  276,  277. 
Fresh  water  clams,  143. 
Frog,  development  of,  301. 

structure  of,  209-211. 
Frogs,  204-206. 
Frogs'  eggs,  294-296. 

Galley  worm,  133. 

Gall  flies,  59-63. 

Gallinse,  253. 

Gang'lion,  a  group  of  nerve  cells, 

123. 

Garden  spider,  129. 
Garter  snakes,  214,  293. 
Gem'mules  (L.  gemma,  bud),  176. 
GSn'era,  plural  of  genus. 
Genus,  28. 
Ge  o  ineV  ri  dae  (Gr.  ge,  earth,  and 

metron,  measure),  85. 
Gibbons,  281. 
Gila  monster,  213. 
Gill    arches,    the   three  or  four 

bony  arches  on  either  side  of 

the  pharynx  of  fishes  bearing 

the  gill  tufts,  198. 
Gills,  organs  of  respiration  used 

by  most  aquatic  animals,  162, 

189,  204,  302. 
Gland,  a  structure  for  secreting  a 

useful  substance,  78. 
Glass  snake,  212. 
Globigerina,  183. 
Glow  worm,  113. 
Golden  robin,  236. 
Goose  barnacles,  140. 
Gordius,  156. 
Gorilla,  281. 
Grackles,  236. 

Grain,  insects  injurious  to,  23. 
Grain  weevil,  108. 
Grape-vine  louse,  97. 
Grandady -long-legs,  130. 
Grantia,  175. 
Grasshopper,  anatomy  of,  123. 


Grasshoppers,  30,  31. 

sounds  of,  37. 
Grass  spider,  126. 
Great  horned  owl,  262. 

auk,  335. 
Green  frog,  205. 
Green  turtle,  224. 
Ground  hog,  270.  273. 
Gymnophiona,  207. 
Gypsy  moth,  80,  126. 

Hairy  woodpecker,  247. 

Halibut,  194. 

Hares,  271. 

Harlequin  bug,  106. 

Harvest  flies,  93. 

Harvestmen,  130. 

Hawk  moths,  73,  74. 

Hawkbill  turtle,  224. 

Hawks,    12,   248,  249,  253,  254, 

255,  256. 
Hearing,  307. 
Heart  of  Amphibian,  210. 

of  crayfish,  136. 

of  mammal,  287. 

of  reptile,  226. 
Hedgehogs,  276. 
Heel  fly,  49. 
Helix,  149. 
Hellbender,  203. 
Hellgramite,  116. 
Heloderma,  213. 
He  mlp'  te  ra  (Gr.  Aemi,  half,  and 

pteron,  wing),  26,  91-107. 
Hen  hawk,  251. 
Hermit  crab,  173,  138. 
Herons,  254,  255. 
Herrings,  190. 
Hessian  fly,  50,  125. 
Hgterop'tera,  104. 
Hibernation,  passing  the  winter 

in  a  dormant  condition,  31. 
High-holer,  246,  250. 
Hippocampus,  193. 


INDEX   AND   GLOSSARY 


361 


Hirudo,  161. 

Holothuroi'dea,  166. 

Honey  bee,  52-54,  121,  298. 

Honey  dew,  57. 

Hop  louse,  24,  97. 

Hornet,  56. 

Horn  tail,  331. 

Horse  hair  worms,  156,  167. 

Horse  bot,  330. 

Horse,  limb  of,  353. 
skeleton  of,  266. 

Horses,  266,  266,  347-350. 

Host,  323. 

House  flies,  24,  45. 

Humming  birds,  244,  249. 

Hydra,  168-170,  344. 

Hydroids,  170,  171,  172. 

Hyla,  205,  206. 

Hymenop'tera  (Gr.  hymen,  mem- 
brane, andpteron,  wing),  27, 
62-68. 

Ichneumon  flies,  63-67,  331. 
Ima'go,  the  adult  form  of  an  in- 
sect, 73,  91. 
Infusoria,  178-180. 
Injurious  insects,  12,  23-24,  34, 

48-50,  124,  125. 
Instinct  in  animals,  55. 
Insec'ta  (L.  in,  in,  and  seco,  cut), 

26,  30-126. 
Insecticide,  a  substance  used  in 

killing  insects,  23,  114. 
Insectiv'ora,  27,  274,  275. 
Insects,  30-126. 
feeling  in,  303. 
hearing  in,  308. 
injurious,  12,  23,  24,  34,  48- 

50,  124,  125. 
parasitic,  329-333. 
preservation  of,  16. 
smell  in,  307. 
structure  of,  121,  128. 
taste  in,  306. 


lo,  311. 

Itch  mite,  131,  328. 

Jaguar,  276. 

Jar  fly,  94. 

Jays,  235. 

Javelin  bat,  274. 

Jellyfish,  173,  174,  296. 

Jigger,  131. 

June  beetle,  110. 

Kallima  butterfly,  313,  314. 
Katydid,  31,  315. 
Kangaroos,  262,  263. 
Killing  of  animals,  18,  114. 
Kingbird,  230,  232. 
Kissing  bug,  105. 

Labium,  lower  lip,  32,  42. 
Labrum,  upper  lip,  32,  42. 
Ladybird  beetles,  101,  102,  114. 
Lamellicorn  beetles,  110. 
Lamprey  eel,  187-188. 
Larva,  the  first  active  young  stage 

of  many  animals,  39,  90,  207, 

208,  298,  301,  302. 
Leaf  rollers,  86. 
Leaf  butterfly,  313,  314. 
Leaf-eating  beetles,  115. 
Leeches,  150-162. 
Lemurs,  280. 
Leopard  frog,  206. 
Lepidop'tera  (Gr.  lepis,  scale,  and 

pteron,  wing),  26,  68-91. 
Lepidosiren,  195. 
Lepomis,  193. 
Leporidse,  271. 
Lernea,  333. 
Leucoselenia,  175. 
Lice,  24,  67,  95-98,  328,  329. 
Lightning  bug,  112. 
Limax,  149. 
Liver  fluke,  326. 
Linnaeus,  28. 
Lion,  276. 


362 


INDEX   AND   GLOSSARY 


Lion,  mountain,  276. 
Lizards,  211-213. 

egg  of,  293. 
Lobster,  136,  341. 
Locust,  anatomy  of,  32-34,  123. 

borer,  111. 

Carolina,  36. 

red-legged,  35. 

Rocky  Mountain,  12,  35. 
Loggerhead  turtle,  224. 
Long-eared  owl,  253,  258. 
Longicorn  beetles,  111. 
Lucanus,  111. 
Lumbricus,  152. 
Lung  fishes,  194. 
Lungs  of  salamanders,  201. 
Lynx,  275,  276. 

Mackerel,  192,  193. 
Madrepor'ic,  162. 
Maggot,  47,  122. 
Magpie,  235. 
Malacostraca,  299. 
Malarial  parasite,  183. 
Malaria  mosquito,  41,  42. 
Mamma/lia  (L.  mamma,  breast), 

27,  261-292. 

Mammal,  structure  of,  283-292. 
Mammoth,  335,  336. 
Man,  age  of,  335. 
Manatee,  264. 
Mandibles,  32. 
Man-eater,  188,  277. 
Mantle,  145. 
Maple  borer,  89. 

gall,  61. 

louse,  97. 

scale,  103. 
Marmoset,  280. 
Marmots,  270,  273. 
Marsu'pia'lia   (L.    marsupium,  a 

pouch),  27,  263,  264. 
Marten,  278. 
Mastodon,  351. 


Maxillae,  32. 

May  flies,  117. 

Meadow  lark,  24,  236. 

Mealy  bug,  103. 

Measuring  worms,  85,  315. 

Medicinal  leech,  151. 

Medu'sje,  172. 

Mgso  hip'pus,  348. 

Metamor'phosis  (Gr.  meta,  over, 
and  morphe,  form)  the  change 
from  one  stage  to  another  in 
the  development  of  the  young, 
61,  90,  91,  93,  121,  295-302. 

Mice,  270,  271. 

Microscope,  a  convex  lens  or  a 
combination  of  several  such 
lenses  for  magnifying  objects, 
21. 

Migration  of  birds,  24,  260. 

Milk  snake,  214,  216. 

Milkweed  butterfly,  69. 

Millipeds,  132. 

Mim'icry,  214,  321. 

Mink,  278. 

Mite,  131,  327. 

Moa,  335. 

Moc'casin,  214,  219. 

Mole,  275. 

Molting,  shedding  the  outer  skin 
or  feathers,  215,  221. 

Molting  of  crustaceans,  137. 
of  insects,  31. 

Mollus'ca,  26,  142-150. 

Molluscoi'da,  aquatic  worms 
which,  to  the  casual  observer, 
appear  like  plants,  25. 

Monarch  butterfly,  69. 

Monkeys,  280  283. 

Monotremata,  27,  261-263. 

Moose,  267,  269,  330. 

Mosquitoes,  24,  39-45.- 

Moth,  eggs  of,  297. 

Moths,  68,  73-91. 

Mounting  of  animals,  18- 


INDEX  AND   GLOSSARY 


363 


Mourning  cloak,  70. 
Mouth  parts  of  insect,  32. 

of  mosquito,  46. 
Mud  eel,  204. 
Mud  fish,  196. 
Mud  puppy,  203. 
Mud  wasps,  55. 
Mur'idae,  270. 
Mus,  271. 
Museum  pest,  114. 
Muscles,  283-285. 
Mussel,  143,  144. 
Muskrat,  270. 
Mya,  142. 

Myri&p'oda  (Gr.  myroi,  ten 
thousand,  and  poda,  feet),  26, 
132. 

Mysis,  299. 
Mytilaspis,  102. 

Nares,  210. 
Natural  History,  11. 

selection,  322,  347-350. 
Nau'plius,  one  of  the  larval  forms 
of  crustaceans,  299,  300,  333. 
Nautilus,  150. 
Necturus,  203. 

Nem'  a  thel  mm'  thes  (Gr.   nema, 
thread,  and  helminth,  worm), 
25,  155-157. 
Ngrn'atocyst,  168. 
Nemertini,  161. 
Nephrid'ia,    organs  of  excretion 

in  the  lower  animals,  154. 
Nerves,  termination  of,  305,  308. 
Nervous  system  of  bee,  121. 

of  cat,  289. 

of  crayfish,  134. 

of  fish,  197,  198. 

of  frog,  209,  211. 
NeurSp'tera,  26,  116. 
Newt,  199,  200 
Night  walker,  152. 
Noctuidse,  82. 


Nomenclature,  28. 

Notochord,  186,  187. 

Nuthatches,  241,  245. 

Nut  weevil,  107. 

Nymph,  the  young  form  of  insects 
which  do  not  have  a  complete 
metamorphosis,  31,  36,  298. 

Oak  galls,  60,  67. 

Oak-leaf  rollers,  87. 

Ocelli,  simple  eyes  of  insects,  34. 

Odonata,  26,  118. 

Opalina,  327. 

Operculum,  189. 

Ophidia,  213,  221. 

Ophion,  66. 

Ophisau'rus,  212. 

Ophiuroi'dea,  166. 

Opossum,  263,  264. 

Orang-outang,  282. 

Orchard,  birds  affecting,  24. 

Order,  the  several  groups  of  an- 
imals composing  a  class  or 
subclass,  26. 

Organism,  an  individual  plant  or 
animal,  11. 

Origin  of  species,  342-354. 

Orioles,  235. 

Or'nithorhyn'chus,  the  duck  mole, 
262. 

Orthop'tera  (Gr.  orthos,  straight, 
and  pteron,  wing),  26,  30-38. 

Ovip'arous,  producing  eggs,  213 

Ovipositor  (L.  ovum,  egg,  and 
positum,  placed),  a  projection 
from  the  end  of  the  abdomen 
of  insects  used  in  egg-laying, 
33,  57,  94. 

Owls,  12,  32,  248,  252,  253,  258. 

Owlet  moths,  82.  84. 

Ox  bot,  24,  49,  330. 

Oyster,  143. 
crab,  13&. 

Oyster-shell  scale,  102. 


364 


INDEX  AND   GLOSSARY 


Painted  terrapin,  223. 
Partridge,  254. 
PSr  a  mce'  cium,  178. 
Parasites,  organisms  feeding  on 
living  tissues,  whether  plant 
or  animal, 

of  fish,  332,  333. 

of  honey  bee,  51. 

of  insects,  330-332. 

of  man,  131,  155,  158-160. 
Parasitism,  323-334. 
Par'thenogen'esis,  the  production 
of  young  from  eggs  not  fer- 
tilized,   as    in    some   cases 
among  plant  lice,  ants,  bees, 
and  wasps,  54,  95,  96,  161. 
Passeres,  231. 

Peach  tree  borer,  24,  89,  90. 
Pea  louse,  97. 
Pearl  oysters,  144. 
Pearly  nautilus,  150. 
Pear  slug,  24. 
Peas,  insects  affecting,  24. 
Pea  weevil,  108. 
Perching  birds,  231. 
Peritoneum,  198,  210,  286. 
Pernicious  scale,  98. 
Petrel,  fulmar,  334. 
Petromyzon,  180. 
Pewee,  232. 
Phoebe,  232. 
Phorodon,  97. 
Photinus,  112. 

Phyla,  same  as  subkingdom,  28. 
Phylloxera,  97. 
Physiology,  11. 
Pieris,  71. 
Pigeon  hawk,  264. 
Pigeon,  wild,  338. 
Pill  bugs,  140. 
Pilot,  218,  219. 
Pimpla  inquisitor,  64. 
Pine-bark  beetle,  110. 
Pine  tree  borer,  112. 


Pinnipg'dia,  279. 

Pisces,  27. 

Puma,  276. 

Planaria,  160. 

Plantigrade,  266. 

Plant  lice,  95-98. 

Plastron,  223. 

Plat' yhelmin'  thes  (Gr.  platys, 
flat,  and  helmins,  worm),  25, 
157-161. 

Plethodon,  201. 

Pleura,  286. 

Pleuronec'tes,  194. 

Plum  curcu'lio,  107. 

Poisonous  lizard,  218. 
snakes,  313. 

Polar  bear,  278. 

Pollina'tion  by  insects,  54,  62. 

Pol'yp,  a  fixed  individual  animal 
of  the  Coelenterata,  170. 

Polyphemus,  75. 

Pond  snail,  147,  148. 

Porlf'era,  25,  167,  176-177. 

Porpoises,  264. 

Potassium  cyanide,  19. 

Potato  beetle,  115. 

Prairie  dog,  270. 

Preservation  of  material,  15. 

PrTmates  (L.  primum,  first),  28, 
280-283. 

Proglot'tides,  159. 

Proinethea,  76,  297. 

Protective  coloration,  313-823. 

Proteus,  203. 

Pro'tochorda'ta,  27. 

PrO'toplasm,  the  semi-liquid  ma- 
terial forming  the  greater 
part  of  the  cells,  179,  180. 

PrOtozo'a  (Gr.  protos,  first,  and 
zoon,  animal),  25,  178-184. 

Pseu'dopods  (Gr.  pseudeo,  false, 
and  poda,  feet),  182. 

Ptarmigan,  319,  320. 

Pulex,  329. 


INDEX  AND   GLOSSARY 


365 


Pupa,  the  last  stage  in  the  develop- 
ment of  an  insect  before  as- 
suming the  adult  form,  40,  91, 
298. 

Pupate,  to  transform  into  the 
state  of  a  pupa,  74. 

Python,  219,  220,  352. 

Quahog,  142. 

Quail,   incorrect  name  for  bob- 
white,  318. 
Queen,  52,  55,  66. 

Rabbits,  214,  216,  334,  836. 

Racer,  214,  216. 

Rain  worms,  *52. 

Raja,  189. 

Rana,  205. 

Raptores,  248. 

Rats,  270,  271. 

Rattlesnake,  217,  318. 

Rays,  187,  189. 

Red-backed  salamander,  201. 

Red  bat,  278. 

Red-tailed  hawk,  251,  256. 

Reed  bird,  235. 

Regeneration,  the  renewal  of  a 

lost  part,  154. 
Reindeer,  23,  267. 
Reproduction  in  animals,  844. 
Reptilia,  27,  211-226. 
Rhizop'oda  (Gr.   rhiz,  root,  and 

poda,  feet),  180. 
Rice  bird,  235. 
Roaches,  88. 

Robin,  242,  246,  247,  258,  259. 
Rocky  mountain  goat,  266,  267. 

locust,  12,  85,  259. 
Rodentia  (L.  rodens,  gnawing),  28, 

269. 

Rose  aphids,  96. 

Rose-breasted  grosbeak,  236,  237. 
Rose,  insects  affecting,  59. 
Rose  scale,  103. 


RO'tifers,  microscopic  worms  of  ten 
present  in  stagnant  water,  161 . 

Round  worms,  155,  157,  325. 

Rudimentary  structures,  those 
which  by  evolution  have  be- 
come too  small,  to  be  of  use  as 
the  toe  on  either  side  of  the 
foot  of  a  cow  or  pig,  352. 

Ru'minants,  hoofed  animals  which 
chew  the  cud,  268,  853. 

Sacculi'na,  332. 
Salamanders,  200-204. 
Salmon,  191,  340. 
Salvelinus,  192. 
Sand  dollars,  166. 
Sand  wasps,  55, 
Sanina,  89. 

San  Jose  scale,  24,  98-102. 
Saw  fishes,  189. 
Sawflies,  57-59. 

Scale    insects,    sucking    insects 
which  excrete  material  form- 
ing a  covering  for  the  body, 
23,  24,  98-104. 
Sceleporus,  212. 
Scolopendra,  133. 
Scomber,  192,  193. 
Scorpion,  132. 
Screech  owl,  253,  258. 
Scurfy  scale,  103. 
Sea  anem'one,  174,  806. 

cow,  264,  335. 

cucumber,  166. 

horse,  193. 

lily,  167. 

lion,  279,  280,  887. 
Seal,  280,  337. 
Sea  urchin,  164-166. 
Senses  of  animal,  303-810. 
Serous  membranes,  286. 
Sertularia,  172. 
Sesia  acerni,  89. 
Sesiidse,  89. 


366 


INDEX   AND   GLOSSARY 


Seventeen-year  cicada,  92,  298. 
locust,  92,  298. 

Shad,  191,  334. 

Shade  trees,  insects  enemies  of, 
23,  79,  83. 

Sharks,  187-189. 

Sharp-shinned  hawk,  251,  254. 

Sheep  tick,  51. 

Shellfish,  142-147. 

Ship  worm,  144. 

Shrew,  274,  275. 

Shrimp,  141,  300. 

Silk  worm  culture,  23. 

Silk  worms,  75-78. 

Silver-fish,  24. 

Silver-spotted  fritillary,  70. 

Siren,  204. 

Siren'ia,  28,  264. 

Skate,  189. 

Skeleton  of  cat,  290. 
horse,  266. 

Skinks,  212. 

Slipper  animalcules,  178. 

Sloths,  264. 

Slug,  148. 
rose,  59. 
pear,  59. 

Smell,  306,  307. 

Snail,  147,  148. 

Snake  embryo,  303. 

Snakes,  213-221. 

Snapping  turtle,  223. 

Snout  beetles,  107. 

Snowy  owl,  321. 

So'mites  (Gr.  soma,  body),  33. 

Song  sparrow,  239,  240. 

Sow  bug,  140. 

Sparrow  hawk,  251,  255. 

Sparrows,  236-240. 

Species,  28. 

Sperm,  the  male  cell  which,  unit- 
ing with  the  egg,  fertilizes  it, 
thus  rendering  it  capable  of 
developing  into  a  new  ani- 
mal, 170,  172. 


Spermatozo'a,  plural  of  sperma- 
tozoon. 

Spermatozoon,  same  as  sperm. 

Sphinx  moths,  73. 

Spider  crab,  316. 

Spiders,  125-130. 

Spinnerets  of  spiders,  129. 

Spinning  moths,  74. 

Spiny  ant  eater,  263. 

Splint  bone,  266,  353. 

Sponges,  175-177. 

Spontaneous  generation,  the  de- 
velopment of  a  living  body 
from  dead  material,  342-344, 

Spores,  182,  343. 

Sporozd'a,  182. 

Spring  peeper,  206. 

Spruce  beetles,  109. 

Squalis,  187. 

Squamata,  211. 

Squash  bug,  24,  105. 

Squid,  149. 

Squirrels,  270. 

Stable  fly,  46. 

Stag  beetle,  111. 

Starfish,  161,  165. 

Stegomy'ia,  41. 

Sternum,  33. 

Stinging  insects,  51-56. 

Strawberry  weevil,  24,  109. 

Strongylus,  325. 

Struggle  for  existence,  334. 

Subkingdoms,  25-28. 

Suckers,  190. 

Sunfishes,  193. 

Survival  of  the  fittest,  334. 

Swallows,  240. 

Swallowtails,  71. 

Swifts,  244,  249,  250. 

Symbio'sis,  323. 

Syrphus  flies,  48. 

Tach'ina  flies,  47,  332. 
Tadpole,  207,  208,  301,  302. 
Taenia,  158,  327. 


INDEX   AiND   GLOSSARY 


367 


Talons,  249. 

Tape  worms,  158,  326,  327. 

Tarantulas,  126. 

Taste,  305. 

Teleos'tomi,  185,  189-199. 

Tendon,  284. 

Tent  caterpillar,  78-82. 

Terguin,  33. 

Terrapin,  223. 

Terrestrial,  living  on  land. 

Thales'sa,  66,  331. 

Thainno'phis,  214. 

Thorax,  32. 

Threadworms,  155-157. 

Thrushes,  242,  243,  247. 

Tick,  51,  327,  328. 

Tiger,  276. 

Tin'ea,  88,  89. 

Tine'idse,  88. 

Tine'ola,  88. 

Titmouse,  242. 

Toad,  23,  206,  267. 

eggs,  294,  295. 

Tobacco,  insects  affecting,  23. 
Tomato-worm  moth,  74. 
Torpedo,  189. 
Tortoises,  222,  223. 
Tortricidae,  86. 
Tra'chea,  34. 
Trapdoor  spider,  128. 
Tree  frog,  205,  206,  316. 
Trichina,  155,  156,  325. 
Troch  el  min'  thes     (Gr.    trochos, 
wheel,  and  helmins.  worm), 
aquatic  worms,  25. 
Trout,  192. 
Tulip  tree  scale,  103. 
Turtle,  egg  of,  293. 
Turtles,  222,  224. 
Tussock  moths,  79,  83. 
Tympanic  membrane,  397,  308. 

Umbo,  145. 

Ungula'ta  (L.  unguis,  nail),  mam- 
mals bearing  hoofs,  28,  265. 


Unio,  143. 
Urchins,  165. 
Urodela,  200-204. 
Ur'sidse,  279. 

Vampire  bats,  274. 
Vanessa,  71. 
Variation,  347-352. 

in  color,  278,  279,  320-323. 
Veliger,  299. 

Venomous,  poisonous,  216,  218. 
Ventricle,  the  cavity  of  the  heart 

sending  forth  blood,  289. 
Venus,  142. 

Vermes,  worms,  150,  161. 
Vermiform  appendix,  353. 
Vertebrata,  27,  185-292. 
Vesper  sparrow,  239. 
Vinegar  eel,  155. 
Vireo,  242,  243,  258. 
Vivip'arous,  giving  birth  to  young 

instead  of  laying  eggs. 
Vocal  cords,  287. 
Vorticel'la,  180. 
Vulpes,  277. 
Vulture,  249. 


Walking  stick,  37,  314. 

Walruses,  279. 

Warble-fly,  330. 

Warblers,  258. 

Wasps,  55,  59. 

Water  boatman,  106. 

Water  fleas,  138,  139. 

Water  moccasin,  214. 

Water  snake,  215. 

Weasel,  277,  278,  322. 

Weevils,  23,  24,  107. 

Whales,  264,  352. 

Wheat,  insects  affecting,  23,  50, 

57. 

midge,  51. 

Whip-poor-will,  245,  318. 
Wildcat,  275,  276. 


868 


INDEX   AND   GLOSSARY 


Wild  pigeon,  338. 
Wire  worms,  118. 
Witch-hazel  galls,  61. 
Wolves,  277 

Woodchuck,  270,  273,  337. 
Woodcock,  317. 
Wood  lice,  141. 
Woodpecker,  245,  259,  293. 
Wood  thrush,  243,  247. 
Wood  tortoise,  222. 
Workers,  52,  56. 
Worms,  25,  26,  150-161. 

parasitic,  324. 
Wrens,  240,  241,  246. 


Yearbooks  of  Department  of  Ag- 
riculture, 23. 

Yellow  fever  mosquito,  41. 
Yellowjacket,  55. 
Young,  development  of,  294-303. 

Zoaea,  299. 

Zoology,  11. 
economic,  12. 

Zo'ophytes  (Gr.  zoon,  animal, 
and  phyton,  plant),  plantlike 
animals,  such  as  hydroids, 
172. 


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